MARIJUANA GROWERS HANDBOOK

 

 

Part I
General Infromation

Preface

In 1969, Richard Nixon initiated Operation Intercept, a pro-
gram designed to stem the flow of Mexican marijuana into this
country. The program forced Mexico to use paraquat on its mari-
juana fields. In similar actions, pressure was put on Thailand, Col-
ombia, and Jamaica to curtail imports to the U.S.
Domestic smokers became increasingly alarmed at the reports
of lung damage after smoking paraquat-sprayed marijuana. In fact,
at the time, Dr. Carlton Turner, currently President Reagan's Drug
Policy Advisor, developed a kit to determine whether the marijuana
a smoker had purchased was contaminated. In addition, infections
were reported from smoking imported marijuana which was con-
taminated by animal feces and mold.
In this climate of health fears and supply shortage, Ed Rosen-
thal and his colleague Mel Frank wrote Marijuana Grower's Guide,
which was the most monumentally successful book of its kind ever
published. Domestic cultivators took the technology found in Mari-
juana Grower's Guide and developed their own indoor and outdoor
plots, no longer willing to rely on foreign supply. The more the
government stepped up its eradication attempts aimed at imports,
the more mini-gardens and mini-farms began to develop in the U.S.
In simple-to-understand language, Marijuana Grower's Guide made
experts out of gardening hobbyists.
Marijuana cultivation technology has accelerated since Mari-
juana Grower's Guide was written. Advances in lighting
technology, hydroponics and propagation left a void of serious
literature on the subject. Marijuana Growers Handbook is a com-
pletely new book which covers all phases of cultivation, including
state-of-the-art techniques.
Most experts agree that U.S. growers are the finest in the
world. They can get a good yield from the smallest space and have
developed hybrids of incredible quality. This indicates that many
growers use sophisticated techniques. This book was written to help
these people with their gardens, as well as helping novices who are
growing for the first time.

The Wall Street Journal recently estimated that there are bet-
ween 20 and 30 million regular users of marijuana in this country.
Other sources put the figure at 50,000,000 users of marijuana in this
country. High Times calculates that 50% of the marijuana used in
this country is domestic. Marijuana will not go away.
Cowardly and reactionary politicians who have maintained
prohibition will soon see marijuana legalized. Realistic politicians
who see the damage that the marijuana laws have done to the socie-
ty will change the laws so that they can tax and regulate marijuana.
Only homegrowers will be free of the market and government
regulation. We are ready for legalization, too. We have the
technology for growing superior marijuana and the tools for doing
it.
Marijuana prohibition was initiated because of the people who
smoked it. The laws continue in effect today for those same
reasons. Politicians don't like people who think for themselves, are
independent, and who recognize bullshit. They would prefer for
each citizen to become a subject, a ward of the state, who is depen-
dent on government for making his/her life decisions. Marijuana
tends to let us develop different sets and set perceptions, to see the
world a little differently. To change not only what we think but how
we think. That's what scares the regulators.

Precaution

It is a felony to cultivate marijuana in 49 of the 50 states (it is
legal in Alaska). It is legal or tolerated in only a few countries:
Holland, India, and Nepal.
Growers use precaution when setting up their gardens. They
make sure that their activity arouses no suspicion and that the
garden and its contents cannot be seen by unintended observers.

 

Artificial lighting, usually the main source of light for indoor
gardeners, can draw quite a bit of electricity. Electrical systems
should be adequate to support the electrical draw. If a large amount
of electricity is used, the utility company may investigate the situa-
tion for shorts or other drains, including a surreptitious garden.
Growers are circumspect about discussing their gardens. The
smartest ones use only the "need to know theory" - that anyone
who doesn't need to know doesn't know. Envy, jealousy, and even
misplaced morality have made informers of ex-friends.

Chapter One
Marijuana: The Plant

Cannabis probably evolved in the Himalayan foothills, but its
origins are clouded by the plant's early symbiotic relationship with
humans. It has been grown for three products-the seeds, which are
used as a grainlike food and animal feed and for oil; its fiber, which
is used for cloth and rope; and its resin, which is used medically and
recreationally since it contains the group of psychoactive substances
collectively known as Tetra-hydrocannibinol, usually referred to as
THC. Plants grown for seed or fiber are usually referred to as hemp
and contain small amounts of THC. Plants grown for THC and for
the resin are referred to as marijuana.
Use of cannabis and its products spread quickly throughout
the world. Marijuana is now cultivated in climates ranging from the
Arctic to the equator. Cannabis has been evolving for hundreds of
thousands of generations on its own and through informal breeding
programs by farmers. A diverse group of varieties has evolved or
been developed as a result of breeders attempts to create a plant
that is efficient at producing the desired product, which flourishes
under particular environmental conditions.
Cannabis easily escapes from cultivation and goes "wild". For
instance, in the American midwest, stands of hemp "weed" remain
from the 1940's plantings. These plants adapt on a population level
to the particular environmental conditions that the plants face; the
stand's genetic pool, and thus the plants' characteristics, evolve
over a number of generations.
Varieties differ in growth characteristics such as height, width,
branching traits, leaf size, leaf shape, flowering time, yield, poten-
cy, taste, type of high, and aroma. For the most part, potency is a
factor of genetics. Some plants have the genetic potential of pro-
ducing high grade marijuana and others do not. The goal of the
cultivator is. to allow the high THC plants to reach their full
potential.
Marijuana is a fast growing annual plant, although some
varieties in some warm areas over winter. It does best in a well-
drained medium, high in fertility. It requires long periods of
unobstructed bright light daily. Marijuana is usually dioecious;
plants are either male or female, although some varieties are
monoecious - they have male and female flowers on the same
plant.
Marijuana's annual cycle begins with germination in the early
spring. The plant grows vigorously for several months. The plant
begins to flower in the late summer or early fall and sets seed by late
fall. The seeds drop as the plant dies as a result of changes in the
weather.
Indoors, the grower has complete control of the environment.
The cultivator determines when the plants are to be started, when
they will flower, whether they are to produce seed and even if they
are to bear a second harvest.

Chapter Two

Choosing A Variety

Gardeners can grow a garden with only one or two varieties or
a potpourri. Each has its advantages. Commercial growers usually
prefer homogeneous gardens because the plants taste the same and
mature at the same time. These growers usually choose fast matur-
ing plants so that there is a quick turnaround. Commercial growers
often use clones or cuttings from one plant so that the garden is
genetically identical; the clones have exactly the same growth habits
and potency.
Homegrowers are usually more concerned with quality than
with fast maturity. Most often, they grow mixed groups of plants so
they have a selection of potency, quality of the high, and taste.
Heterogeneous gardens take longer to mature and have a lower
yield than homogeneous gardens. They take more care too, because
the plants grow at different rates, have different shapes and require
varying amounts of space. The plants require individual care.
Marijuana grown in the United States is usually one of two
main types: indica or sativa. Indica plants originated in the Hindu-
Kush valleys in central Asia, which is located between the 25-35
latitudes. The weather there is changeable. One year there may be
drought, the next it might be cloudy, wet, rainy or sunny. For the
population to survive, the plant group needs to have individuals
which survive and thrive under different conditions. Thus, in any
season, no matter what the weather, some plants will do well and
some will do poorly.
Indica was probably developed by hash users for resin content,
not for flower smoking. The resin was removed from the plant. An
indication of indica's development is the seeds, which remain
enclosed and stick to the resin. Since they are very hard to discon-
nect from the plant, they require human help. Wild plants readily
drop seeds once they mature.
Plants from the same line from equatorial areas are usually
fairly uniform. These include Colombians and central Africans.
Plants from higher latitudes of the same line sometimes have very
different characteristics. These include Southern Africans, Nor-
thern Mexicans, and indicas. The plants look different from each

 

other and have different maturities and potency. The ratio of THC
(the ingredient which is psychoactive) to CBD (its precursor, which
often leaves the smoker feeling disoriented, sleepy, drugged or con-
fused) also varies.
High latitude sativas have the same general characteristics as
other sativas: conical form, long bladed leaves, wide spacing be-
tween branches, and vigorous growth.
Indicas do have some broad general characteristics: they tend
to mature early, have compact short branches and wide, short
leaves which are dark green, sometimes tinged purple.
Indica buds are usually tight, heavy, wide and thick rather than
long. They smell "stinky", "skunky", or "pungent" and their
smoke is thick - a small toke can induce coughing. The best in-
dicas have a relaxing "social high" which allow one to sense and
feel the environment but do not lead to thinking about or analyzing
the experience.
Cannabis sativa plants are found throughout the world. Potent
varieties such as Colombian, Panamanian, Mexican, Nigerian,
Congolese, Indian and Thai are found in equatorial zones. These
plants require a long time to mature and ordinarily grow in areas
where they have a long season. They are usually very potent, con-
taining large quantities of THC and virtually no CBD. They have
long, medium4hick buds when they are grown in full equatorial
sun, but under artificial light or even under the temperate sun, the
buds tend to run (not fill out completely). The buds usually smell
sweet or tangy and the smoke is smooth, sometimes deceptively so.
The THC to CBD ratio of sativa plants gets lower as the plants
are found further from the equator. Jamaican and Central Mexican
varieties are found at the 1 5-2Oth latitudes. At the 3Oth latitude,
varieties such as Southern African and Northern Mexican are
variable and may contain equal amounts of THC and CBD, giving
CHART 2-1: The Varieties at a Glance
Variety Maturity Outdoor Size Branching Pattern Bud Type Aroma High Buds Color Comments
(in feet) Density of Bud (flowers)
Height Width Indoors
Afghani mid- 4-8 3-6 squat, compact, thick, heavy heavy, rounded, dark The standard corn-
& Kush Sept. short sidebranches, dense, pungent, tiring, dense green, mercial plant. Quality
-Oct. thick webbed leaves short, skunky- stupefying purple varies within
rounded fruity population.
Colombian late 7-12 4-7 conical, X-mas med. thick, sweet, spacy, Tends to run green, Rarely seen commer
Nov.-Jan. tree, long branches 4-8" long, fruity, thought- long flower some red cially. Needs lots of
at bottom, tapering light to light provoking, stem, sparse light and warmth to
at the top, thin long medium strong flowered develop thick colas.
leaves density _________ ____________________
Indian mid Nov.- 8-12 4-6 long internodes, big big, thick, med strong, large fluffy light Will run without
(Central) mid Dec. leaves, strong firm 7-12" long; fruity- active, buds green, intense light.
branches, elongated light-wt. skunky social red Susceptible to
conical shape flowers on pistils fusarium wilt.
tiny cola
branches.
Jamaican late 6-10 3-6 conical, but squat- long thin light, medium, thin, long runs light Adaptable, good

 

Oct.-Dec. ter than Col. Med. colas sweet, active, under low light green weather resistance.
leaves, medium w/buds musky social Susceptible to
branching 11/2 "-3" fusarium wilt.
long
Mexican Oct.-early 8-15 41/2-9 elongated long, thin light, weak, long thin light Vigorous plants, fast
(Northern) Nov. X-mas tree, long 12"-24" sweet slightly mature well green, starters. Some cold-
branches, medium- colas perfume, heavy, red resistance.
sized leaves spicy sleepy
Mexican Nov.-Dec. 8-14 4 1/2-9 shorter than long thin sweet comes on long, thin, may very' light Hybridizes well with
(Southern) northern 12 "-18" quick; run a little colored, Afghani.
colas intense, red hairs
soaring
Moroccan Aug.- 4-9 21/2-5 some sidebranching, thick, round med. weak, thin buds dark Good breeding
Sept. but most effort in ed, 3"-6" sweet to buzzy mature easily green material, lots of
tops long skunky variation.
Nigerian mid 6-12 4-7 X-mas tree with med. thick, dry- very thick, med. medium Vigorous warm
Nov.-mid strong side dense; runs sweet, strong, length, may green weather plant. Needs
Dec. branches; long, in low light perfume bell- run; needs light to mature.
highly serrated musk ringing, lots of light
fingers paralyzing
Thai Dec.-Jan. 5-9 4-8 asymmetrical, long dense, medium, strong fluffy, medium Many hermaphodites
and con- branches seek open under high dry- druggy, mature Se- green make growing hard.
tinuing space light runs sweet, has energ quentially Buds ripen but plant
otherwise spicy over months sends out new
flowers.
Southern Aug.- 5-9 4-6 elongated conical med. thick, heavy uplifting, thin buds light Very variable. Good
African Oct. lower branches may be sweet to social mature easily green breeding material.
angle up sharply; somewhat spicy
thin-bladed leaves loose &
often heavily leafy
serrated

All of the descriptions are tentative guidelines. They are affected by cultivation technique, microenvironmental conditions, variations in climate, nutrients
available, latitude and other factors. Often, several distinctive varieties can be found in the same areas. The most common varieties are described.
the smoker a buzzy, confusing high. These plants are used mostly
for hybridizing. Plants found above the 3oth latitude usually have
low levels of THC, with high levels of CBD and are considered
hemp.
If indica and sativa varieties are considered opposite ends of a
spectrum, most plants fall in between the spectrum. Because of
marijuana and hemp's long symbiotic relationship with humans,
seeds are constantly procured or traded so that virtually all popula-
tions have been mixed with foreign plants at one time or another.
Even in traditional marijuana-growing countries, the mari-
juana is often the result of several crossed lines. Jamaican ganja,
for example, is probably the result of crosses between hemp, which
the English cultivated for rope, and Indian ganja, which arrived
with the Indian immigrants who came to the country. The term for
marijuana in Jamaica is ganja, the same as in India. The traditional
Jamaican term for the best weed is Kali, named for the Indian killer
goddess.

 

Chapter Three

Growth and Flowering

The cannabis plant regulates its growth and flowering stages by
measuring changes in the number of hours of uninterrupted
darkness to determine when to flower. The plant produces a hor-
mone (phytochrome) beginning at germination. When this chemical
builds up to a critical level, the plant changes its mode from
vegetative growth to flowering. This chemical is destroyed in the
presence of even a few moments of light. During the late spring and
early summer there are many more hours of light than darkness and
the hormone does not build up to a critical level. However, as the
days grow shorter and there are longer periods of uninterrupted
darkness, the hormone builds to a critical level.
Flowering occurs at different times with different varieties as a
result of the adaption of the varieties to the environment. Varieties
from the 3oth latitude grow in an area with a temperate climate and
fairly early fall. These plants usually trigger in July or August and
are ready to harvest in September or October. Southern African
varieties often flower with as little as 8 or 9 hours of darkness/15 to
16 hours of light. Other 3oth latitude varieties including most in-
dicas flower when the darkness cycle lasts a minimum of 9 to 10
hours. Jamaican and some Southeast Asian varieties will trigger at
11 hours of darkness and ripen during September or October.
Equatorial varieties trigger at 12 hours or more of darkness.
This means that they will not start flowering before late September
or early October and will not mature until late November or early
December.
Of course, indoors the plants' growth stage can be regulated
with the flick of a switch. Nevertheless, the plants respond to the ar-
tificial light cycle in the same way that they do to the natural
seasonal cycles.
The potency of the plant is related to its maturity rather than
Chronological age. Genetically identical 3 month and 6 month-old
plants which have mature flowers have the same potency. Starting
from seed, a six month old plant flowers slightly faster and fills out
more than a 3 month old plant.
Chapter Four

Choosing a Space

Almost any area can be converted to a growing space. Attics,
basements, spare rooms, alcoves and even shelves can be used.
Metal shacks, garages and greenhouses are ideal areas. All spaces
must be located in an area inaccessible to visitors and invisible from
the street.
The ideal area is at least 6 feet high, with a minimum of 50
square feet, an area about 7 by 7 feet. (Square footage is computed
by multiplying length times width.) A single 1,000 watt metal halide
or sodium vapor lamp, the most efficient means of illuminating a

 

garden, covers an area this size.
Gardeners who have smaller spaces, at least one foot wide and
several feet long, can use fluorescent tubes, 400 watt metal halides,
or sodium vapor lamps.
Gardeners who do not have a space even this large to spare can
use smaller areas (See the chapter "Novel Gardens").
Usually, large gardens are more efficient than small ones.
The space does not require windows or outside ventilation, but
it is easier to set up a space if it has one or the other.
Larger growing areas need adequate ventilation so that heat,
oxygen, and moisture levels can be controlled. Greenhouses usually
have vents and fans built in. Provisions for ventilation must be
made for lamp-lit enclosed areas. Heat and moisture buildup can be
extraordinary. During the winter in most areas, the heat is easily
dissipated; however, the heat buildup is harder to deal with in hot
weather. Adequate ventilation and air coolers are the answer.

Chapter Five

Preparing the Space

The space is the future home and environment of the plants. It
should be cleaned of any residue or debris which might house in-
sects, parasites or diseases. If it has been contaminated with plant
pests it can be sprayed or wiped down with a 5 % bleach solution
which kills most organisms. The room must be well-ventilated when
this operation is going on. The room will be subject to high humidi-
ty so any materials such as clothing which might be damaged by
moisture are removed.
Since the plants will be watered, and water may be spilled, the
floors and any other areas that may be water damaged should be
covered with linoleum or plastic. High grade 6 or 8 mil polyethylene
drop cloths or vinyl tarps protect a floor well. The plastic should be
sealed with tape so that no water seeps to the floor.
The amount of light delivered to the plant rises dramatically
when the space is enclosed by reflective material. Some good reflec-
tive materials are flat white paint, aluminum (the dull side so that
the light is diffused), white cardboard, plywood painted white,
white polyethylene, silvered mylar, gift wrap, white cloth, or
silvered plastic such as Astrolon. Materials can be taped or tack-
ed onto the walls, or hung as curtains. All areas of the space should
be covered with reflective material. The walls, ceiling and floors are
all capable of reflecting light and should be covered with reflective
material such as aluminum foil. It is easiest to run the material ver
tically rather than horizontally.
Experienced growers find it convenient to use the wide, heavy
duty aluminum foil or insulating foil (sold in wide rolls) in areas
which will not be disturbed and plastic or cloth curtains where the
material will be moved.
Windows can be covered with opaque material if a bright light
emanating from the window would draw suspicion. If the window
does not draw suspicion and allows bright light into the room, it
should be covered with a translucent material such as rice paper,
lace curtains, or aquarium crystal paint.
Garages, metal buildings, or attics can be converted to
lighthouses by replacing the roof with fiberglass greenhouse
material such as Filon~. These translucent panels permit almost all
the light to pass through but diffuse it so that there is no visible im-
age passing out while there is an even distribution of light coming
in. A space with a translucent roof needs no artificial lighting in the
summer and only supplemental lighting during the other seasons.
Overhead light entering from a skylight or large window is very
helpful. Light is utilized best if it is diffused.
Concrete and other cold floors should be covered with in-
sulating material such as foam carpet lining, styrofoam sheeting,
wood planks or wooden palettes so that the plant containers and the
roots are kept from getting cold.

Chapter Six

Plant Size and Spacing

- Manjuana varieties differ not Oflly in their growth rate, but
also in their potential size. The grower also plays a role in determin-
log the size of the plants because the plants can be induced to flower
at any age or size just by regulating the number of hours of uninter-
rupted darkness that the plants receive.
Growers have different ideas about how much space each plant
needs. The closer the plants are spaced, the less room the individual
plant has to grow. Some growers use only a few plants in a space,
and they grow the plants in large containers. Other growers prefer
to fill the space with smaller plants. Either method works, but a
gar den with smaller plants which fills the space more completely
probably yields more in less time. The total vegetative growth in a
Worn containing many small sized plants is greater than a room
co ntaining only a few plants. Since each plant is smaller, it needs
less time to grow to its desired size. Remember that the gardener is
in terested in a crop of beautiful buds, not beautiful plants.
The amount of space a plant requires depends on the height the
plants are to grow. A plant growing 10 feet high is going to be wider
than a 4 foot plant. The width of the plant also depends on cultiva-
don practices. Plants which are pruned grow wider than unpruned
plants. The different growth characteristics of the plants also affect
die space required by each plant. In 1-or 2-light gardens, where the
plants are to grow no higher than 6 feet, plants are given between 1
and 9 square feet of space. In a high greenhouse lit by natural light,
Where the plants grow 10-12 feet high, the plants may be given as
m uch as 80 to 100 square feet.

 

PART II.

Getting Started

Chapter Seven

Planting Mixes

One of the first books written on indoor growing suggested
that the entire floor of a grow room be filled with soil. This method
is effective but unfeasible for most cultivators. Still, the growers
have a wide choice of growing mediums and techniques; they may
choose between growing in soil or using a hydroponic method.
Most growers prefer to cultivate their plants in containers filled
with soil, commercial mixes, or their own recipe of soil, fertilizers,
and soil conditioners. These mixes vary quite a bit in their content,
nutrient values, texture, pH, and water-holding capacity.
Potting soil is composed of topsoil, which is a natural outdoor
composite high in nutrients. It is the top layer of soil, containing
large amounts of organic material such as humus and compost as
well as minerals and clays. Topsoil is usually lightened up so that it
does not pack. This is done using sand, vermiculite, perlite, peat

 

moss and/or gravel.
Potting soil tends to be heavy, smell earthy and have a rich
dark color. It can supply most of the nutrients that a plant needs for
the first couple of months.
Commercial potting mixes are composites manufactured from
ingredients such as bark or wood fiber, composts, or soil condi-
tioners such as vermiculite, perlite and peat moss. They are design-
ed to support growth of houseplants by holding adequate amounts
of water and nutrients and releasing them slowly. Potting mixes
tend to be low in nutrients and often require fertilization from the
outset. Many of them may be considered hydroponic mixes because
the nutrients are supplied by the gardener in a water solution on a
regular basis.
Texture of the potting mix is the most important consideration
for containerized plants. The mixture should drain well and allow
air to enter empty spaces so that the roots can breathe oxygen.
Mixes which are too fine may become soggy or stick together,
Preventing the roots from obtaining the required oxygen. A soggy
Condition also promotes the growth of anaerobic bacteria which
release acids that eventually harm the roots.
A moist potting mix with good texture should form a clump if
it is squeezed in a fist; then with a slight poke the clod should break
up. If the clod stays together, soil conditioners are required to
loosen it up. Vermiculite, perlite or pea-sized styrofoam chips will
serve the purpose. Some growers prefer to make their own mixes.
These can be made from soil, soil conditioners and fertilizers.
Plants grown in soil do not grow as quickly as those in
hydroponic mixes. However many growers prefer soil for aesthetic
reasons. Good potting mixes can be made from topsoil fairly easily.
Usually it is easier to buy topsoil than to use unpasteurized top-
soil which contains weed seeds, insects and disease organisms. Out-
doors, these organisms are kept in check, for the most part, by the
forces of nature. Bringing them indoors, however, is like bringing
them into an incubator, where many of their natural enemies are
not around to take care of them. Soil can be sterilized using a 5%
bleach solution poured through the medium or by being steamed
for 20 minutes. Probably the easiest way to sterilize soil is to use a
microwave. It is heated until it is steaming - about 5 minutes for a
gallon or more.
Potting soils and potting mixes vary tremendously in composi-
tion, pH and fertility. Most mixes contain only small amounts of
soil. If a package is marked "potting soil", it is usually made most-
ly from topsoil.
If the soil clumps up it should be loosened using sand, perlite
or styrofoam. One part amendment is used to 2-3 parts soil. Ad-
ditives listed in Chart 7-2 may also be added. Here is a partial list of
soil conditioners:

 

 

Foam

 

 

Foam rubber can be used in place of styrofoam. Although it
holds water trapped between its open cells it also holds air. About
1.5 parts of foam rubber for every part of styrofoam is used. Pea-
size pieces or smaller should be used.
Gravel

Gravel is often used as a sole medium in hydroponic systems
because it is easy to clean, never wears out, does not "lock up"
nutrients, and is inexpensive. It is also a good mix ingredient
because it creates large spaces for airpockets and gives the mix
weight. Some gravel contains limestone (see "Sand"). This material
should not be used.

 

Lava

Lava is a preferred medium on its own or as a part of a mix. It
is porous and holds water both on its surface and in the irregular
spaces along its irregular shape. Lava is an ideal medium by itself
but is sometimes considered a little too dry. To give it more
moisture-holding ability, about one part of wet vermiculite is mixed
with 3 to 6 parts lava. The vermiculite will break up and coat the
lava, creating a medium with excellent water-holding abilities and
plenty of air spaces. If the mix is watered from the top, the ver-
miculite will wash down eventually, but if it is watered from the
bottom it will remain.
Perlite

Perlite is an expanded (puffed) volcanic glass. It is lightweight
with many peaks and valleys on its surface, where it traps particles
of water. However, it dQes not absorb water into its structure. It
does not break down easily and is hard to the touch. Perlite comes
in several grades with the coarser grade being better for larger con-
tainers. Perlite is very dusty when dry. To eliminate dust, the
material is watered to saturation with a watering can or hose before
it is removed from the bag. Use of masks and respirators is impor-
tant.

 

Rockwool

Rockwool is made from stone which has been heated then ex-
truded into thin strands which are something like glass wool. It ab-
sorbs water like a wick. It usually comes in blocks or rolls. It can be
used in all systems but is usually used in conjunction with drip emit-
ters. Growers report phenomenal growth rates using rockwool. It is
also very convenient to use. The blocks are placed in position or it is
rolled out. Then seeds or transplants are placed on the material.

 

 

 

Sand

Sand is a heavy material which is often added to a mixture to
increase its weight so that the plant is held more firmly. It promotes
drainage and keeps the mix from caking. Sand comes in several
grades too, but all of them seem to work well. The best sand to use
is composed of quartz. Sand is often composed of limestone; the
limestone/sand raises pH, causing micronutrients to precipitate,
making them unavailable to the plants. It is best not to use it.
Limestone-containing sand can be "cured" by soaking in a
solution of water and superphosphate fertilizer which binds with
the surface of the lime molecule in the sand, making the molecule
temporarily inert. One pound of superphosphate is used to S
gallons of water. It dissolves best in hot water. The sand should sit
in this for 6-12 hours and then be rinsed. Superphosphate can be
purchased at most nurseries.
Horticultural sand is composed of inert materials and needs no
curing. Sand must be made free of salt if it came from a salt-water
area.
Spbagnum Moss
Sphagnum or peat moss is gathered from bogs in the midwest.
It absorbs many times its own weight in water and acts as a buffer
for nutrients. Buffers absorb the nutrients and hold large amounts
in their chemical structure. The moss releases them gradually as
they are used by the plant. If too much nutrient is supplied, the
moss will act on it and hold it, preventing toxic buildups in the
water solution. Moss tends to be acidic so no more than 20% of the
planting mix should be composed of it.

 

Styrofoam Pellets

Styrofoam is a hydrophobic material (it repels water) and is an
excellent soil mix ingredient. It allows air spaces to form in the mix
and keeps the materials from clumping, since it does not bond with
other materials or with itself. One problem is that it is lighter than
water and tends to migrate to the top of the mix. Styrofoam is easily
used to adjust the water-holding capacity of a mix. Mixes which are
soggy or which hold too much water can be "dried" with the addi-
tion of styrofoam. Styrofoam balls or chips no larger than a pea
should be used in fine4extured mixtures. Larger styrofoam pieces
can be used in coarse mixes.

Vermiculite
Vermiculite is processed puffed mica. It is very lightweight but
holds large quantities of water in its structure. Vermiculite is
available in several size pieces. The large size seems to permit more
aeration. Vermiculite breaks down into smaller particles over a
period of time. Vermiculite is sold in several grades based on the
size of the particles. The fine grades are best suited to small con-
tainers. In large containers, fine particles tend to pack too tightly,

 

not leaving enough space for air. Coarser grades should be used in
larger containers. Vermiculite is dusty when dry, so it should be wet
down before it is used.
Mediums used in smaller containers should be able to absorb
more water than mediums in larger containers. For instance, seed-
lings started in 1 to 2 inch containers can be planted in plain ver-
miculite or soil. Containers up to about one gallon can be filled
with a vermiculite-perlite or soil-perlite mix. Containers larger than
that need a mix modified so that it does not hold as much water and
does not become soggy. The addition of sand, gravel, or styrofoam
accomplishes this very easily.
Here are lists of different mediums suitable for planting: Below
is a list of the moist mixtures, suitable for the wick system, the
reservoir system and drip emitters which are covered in Chapter 9.

 

CHART 7-1-A: MOIST PLANTING MIXES

 

1) 4 parts topsoil, 1 part vermiculite, 1 part perlite. Moist, con-
tains medium-high amounts of nutrients. Best for wick and hand-
watering.
2) 3 parts topsoil, 1 part peat moss, 1 part vermiculite, 1 part
perlite, 1 part styrofoam. Moist but airy. Medium nutrients. Best
for wick and hand-watering.
3)3 parts vermiculite, 3 parts perlite, 1 part sand, 2 parts pea-
sized gravel. Moist and airy but has some weight. Good for all
systems, drains well.
4) 5 parts vermiculite, S parts perlite. Standard mix, moist. Ex-
cellent for wick and drip emitter systems though it works well for all
systems.
5) 3 parts vermiculite, 1 part perlite, 1 part styrofoam. Medium
dry mix, excellent for all systems.
6) 2 parts vermiculite, 1 part perlite, 1 part styrofoam, 1 part
peat moss. Moist mix.
7) 2 parts vermiculite, 2 parts perlite, 3 parts styrofoam, 1 part
sphagnum moss, 1 part compost. Medium moisture, small amounts
of slow-releasing nutrients, good for all systems.
8) 2 parts topsoil, 2 parts compost, 1 part sand, 1 part perlite.
Medium-moist, high in slow-release of organic nutrients, good for
wick and drip systems, as well as hand watering.
9) 2 parts compost, 1 part perlite, 1 part sand, 1 part lava.
Drier mix, high in slow-release of nutrients, drains well, good for all
systems.
10)1 part topsoil, 1 part compost, 2 parts sand, 1 part lava.
Dry mix, high in nutrients, good for all systems.
11) 3 parts compost, 3 parts sand, 2 parts perlite, 1 part peat
moss, 2 parts vermiculite. Moist, mid-range nutrients, good for
wick systems.
12) 2 parts compost, 2 parts sand, 1 part styrofoam. Drier,
high nutrients, good for all systems.

 

13) 5 parts lava, 1 part vermiculite. Drier, airy, good for all
systems.
Here are some drier mediums suitable for flood systems as well as
drip emitters hydroponic systems (covered in Chapter 9).

 

 

CHART 7-1-B: FLOOD SYSTEM/DRIP EMITTER MIXES

l)Lava

2) Pea size gravel

3) Sand

4) Mixes of any or all of the above

Manure and other slow-releasing natural fertilizers are often
added to the planting mix. With these additives, the grower needs to
use fertilizers only supplementally. Some of the organic amend-
ments are listed in the following chart. Organic amendments can be
mixed but should not be used in amounts larger than those recom-
mended because too much nutrient can cause toxicity.
Some growers add time-release fertilizers to the mix. These are
formulated to release nutrients over a specified period of time,
usually 3, 4, 6 or 8 months. The actual rate of release is regulated in
part by temperature, and since house temperatures are usually
higher than outdoor soil temperatures, the fertilizers used indoors
release over a shorter period of time than is noted on the label.
Gardeners find that they must supplement the time-release fer-
tilizer formulas with soluble fertilizers during the growing season.
Growers can circumvent this problem by using a time-release fer-
tilizer suggested for a longer period of time than the plant cycle. For
instance, a 9 month time-release fertilizer can be used in a 6 month
garden. Remember that more fertilizer is releasing faster, so that a
larger amount of nutrients will be available than was intended.
These mixes are used sparingly.
About one tablespoon of dolomite limestone should be added
for each gallon of planting mix, or a half cup per cubic foot of mix.
This supplies the calcium along with magnesium, both of which the
plants require. If dolomite is unavailable, then hydrated lime or any
agricultural lime can be used.
CHART 7-2: ORGANIC AMENDMENTS
AMENDMENT N P K 1 Part in X Parts Mix
COW MANURE 1.5 .85 1.75 Excellent conditioner,
breaks down over the
growing season. 1 part in
10 parts mix.
CHICKEN MANURE 3 1.5 .85 Fast acting. 1 part in 20
parts mix.
BLOOD MEAL 15 1.3 .7 N quickly available. 1 part

 

in 100 parts mix.
DRIED BLOOD 13 3 0 Very soluble. 1 part in 100
parts mix.
WORM CASTINGS 3 1 .5 Releases N gradually. 1
part in 15 parts mix.
GUANO 2-8 2-5 .5-3 Varies a lot, moderately
soluble. For guano
containing 20/0 nitrogen, 1
part in 15 parts mix. For
8% nitrogen, 1 part in 40
parts mix.
COTTONSEED MEAL 6 2.5 1.5 Releases N gradually. 1
part in 30 parts mix.
GREENSAND 0 1.5 5 High in micronutrients.
Nutrients available over the
season. 1 part in 30 parts
mix.
FEATHERS 15 ? ? Breaks down slowly. 1 part
in 75 parts mix.
HAIR 17 ? ? Breaks down slowly. 1 part
in 75 parts mix.

N = Nitrogen e p = Phosphorous e K = Potassium

Chapter Eight

Hydroponics vs. Soil Gardening

Plants growing in the wild outdoors obtain their nutrients from
the breakdown of complex organic chemicals into simpler water-
soluble forms. The roots catch the chemicals using a combination
of electrical charges and chemical manipulation. The ecosystem is
generally self-supporting. For instance, in some tropical areas most
of the nutrients are actually held by living plants. As soon as the
vegetation dies, bacteria and other microlife feast and render the
nutrients water-soluble. They are absorbed into the soil and are
almost immediately taken up by higher living plants.
Farmers remove some of the nutrients from the soil when they
harvest their crops. In order to replace those nutrients they add fer-
tilizers and other soil additives.
Gardeners growing plants in containers have a closed ecology
system. Once the plants use the nutrients in the medium, their
growth and health is curtailed until more nutrients become available
to them. It is up to the grower to supply the nutrients required by
the plants. The addition of organic matter such as compost or
manure to the medium allows the plant to obtain nutrients for a
while without the use of water-soluble fertilizers. However, once
these nutrients are used up, growers usually add water-soluble
nutrients when they water. Without realizing it, they are gardening
hydroponically. Hydroponics is the art of growing plants, usually
without soil, using water-soluble fertilizers as the main or sole
source of nutrients. The plants are grown in a non-nutritive

 

medium such as gravel or sand or in lightweight materials such as
perlite, vermiculite or styrofoam.
The advantages of a hydroponic system over conventional hor-
ticultural methods are numerous: dry spots, root drowning and
soggy conditions do not occur. Nutrient and pH problems are large-
ly eliminated since the grower maintains tight control over their
concentration; there is little chance of "lockup" which occurs when
the nutrients are fixed in the soil and unavailable to the plant; plants
can be grown more conveniently in small containers; and owing to
the fact that there is no messing around with soil, the whole opera-
tion is easier, cleaner, and much less bothersome than when using
conventional growing techniques.

Chapter Nine

Hydroponic Systems

PASSIVE HYDROPONIC SYSTEMS

 

Most hydroponic systems fall into one of two broad categories:
passive or active. Passive systems such as reservoir or wick setups
depend on the molecular action inherent in the wick or medium to
make water available to the plant. Active systems which include the
flood, recirculating drip and aerated water systems, use a pump to
send nourishment to the plants.
Most commercially made "hobby" hydroponic systems
designed for general use are shallow and wide, so that an intensive
garden with a variety of plants can be grown. But most marijuana
growers prefer to grow each plant in an individual container.

 

 

The Wick System

The wick system is inexpensive, easy to set up and easy to
maintain. The principle behind this type of passive system is that a
length of 3/8 to 78 inch thick braided nylon rope, used as a wick, will
draw water up to the medium and keep it moist. The container,
which can be an ordinary nursery pot, holds a rooting medium and
has wicks running along the bottom, drooping through the holes at
the bottom, reaching down to the reservoir. Keeping the holes in the
container small makes it difficult for roots to penetrate to the reser-
voir. The amount of water delivered to the medium can be increas-
ed by increasing the number, length, or diameter of the wicks in
contact with the medium.
A 1 gallon container needs only a single wick, a three gallon
container should have two wicks, a five gallon container, three
'wicks. The wick system is self-regulating; the amount of water
delivered depends on the amount lost through evaporation or
transpiration.

 

Each medium has a maximum saturation level. Beyond that
point, an increase in the number of wicks will not increase the
moisture level. A 1-1-I combination of vermiculite, perlite, and
styrofoam is a convenient medium because the components are
lightweight and readily available. Some commercial units are sup-
plied with coarse vermiculite. To increase weight so that the plant
will not tip the container over when it gets large, some of the perlite
in the recipe can be replaced with sand. The bottom inch or two of
the container should be filled only with vermiculite, which is very
absorbent, so that the wicks have a good medium for moisture
transfer.
Wick systems are easy to construct. The wick should extend S
inches or more down from the container. Two bricks, blocks of
wood, or styrofoam are placed on the bottom of a deep tray (a
plastic tray or oil drip pan will do fine.) Then the container is placed
on the blocks so that the wicks are touching the bottom of the tray.
The tray is filled with a nutrient/water solution. Water is replaced
in the tray as it evaporates or is absorbed by the medium through
the wick.
A variation of this system can be constructed using an addi-
tional outer container rather than a tray. With this method less
water is lost due to evaporation.
To make sure that the containers fit together and come apart
easily, bricks or wood blocks are placed in the bottom of the outer
container. The container is filled with the nutrient/water solution
until the water comes to just below the bottom of the inner con-
tainer.
Automating this system is simple to do. Each of the trays or
bottom containers is connected by tubing to a bucket containing a
float value such as found in toilets. The valve is adjusted so that it
shuts off when the water reaches a height about 1/2 inch below the
bottom of the growing containers. The bucket with the float valve is
connected to a large reservoir such as a plastic garbage can or 55
gallon drum. Holes can be drilled in the containers to accomodate
the tubing required, or the tubes can be inserted from the top of the
containers or trays. The tubes should be secured or weighted down
so that they do not slip out and cause floods.
The automated wick system works as a siphon. To get it
started, the valve container is primed and raised above the level of
the individual trays. Water flows from the valve to the plant trays as
a result of gravity. Once the containers have filled and displaced air
from the tubes, the water is automatically siphoned and the valve
container can be lowered. Each container receives water as it needs
it.
A simpler system can be devised using a plastic kiddie pool and
some 4 x 4's or a wooden pallet. Wood is placed in the pool so that
the pots sit firmly on the board; the pool is then filled with water up
to the bottom of the pots. The wicks move the water to the pots.
Wick systems and automated wick systems are available from
several manufacturers. Because they require no moving parts, they
are generally reliable although much more expensive than

 

homemade ones, which are very simple to make.
Wick system units can be filled with any of the mixes found in
Chart 7-1-A.

 

The Reservoir System

The reservoir system is even less complex than the wick system.
For this setup all a grower needs to do is fill the bottom 2 or 3 inches
of a 12 inch deep container with a coarse, porous, inert medium
such as lava, ceramic beads or chopped unglazed pottery. The re-
maining portion is filled with one of the mixes containing
styrofoam. The container is placed in a tray, and sits directly in a
nutrient-water solution 2-3 inches deep. The system is automated
by placing the containers in a trough or large tray. Kiddie pools can
aiso be used. The water is not replaced until the holding tray dries.
Passive systems should be watered from the top down once a
month so that any buildup of nutrient salts caused by evaporation
gets washed back to the bottom.
ACTIVE HYDROPONIC SYSTEMS

 

Active systems move the water using mechanical devices in
order to deliver it to the plants. There are many variations on active
systems but most of them fall into one of three categories: flood
systems, drip systems or nutrient film systems.

 

 

The Flood System

The flood system is the type of unit that most people think of
when hydroponics is mentioned. The system usually has a reservoir
which periodically empties to flood the container or tub holding the
medium. The medium holds enough moisture between irrigations to
meet the needs of the plant. Older commercial greenhouses using
this method often held long troughs or beds of gravel. Today, flood
systems are designed using individual containers. Each container is
attached to the reservoir using tubing.
A simple flood system can be constructed using a container
with a tube attached at the bottom of a plastic container and a jug.
The tube should reach down to the jug, which should be placed
below the bottom of the growing container. To water, the tube is
held above the container so that it doesn't drip. The water is poured
from the jug into the container. Next, the tube is placed in the jug
and put back into position, below the growing container. The water
will drain back into the jug. Of course, not as much will drain back
in as was poured out. Some of the water was retained in the growing
unit.
Automating this unit is not difficult. A two-holed stopper is
placed in the jug. A tube from the growing unit should reach the

 

bottom of the reservoir container. Another tube should be attached
to the other stopper hole and then to a small aquarium-type air
pump which is regulated by a timer. When the pump turns on, it
pushes air into the jug, forcing the water into the container. When
the pump goes off, the water is forced back into the jug by gravity.
Several growing units can be hooked up to a large central reservoir
and pump to make a larger system. The water loss can automatical-
ly be replaced using a float valve, similar to the ones used to
regulate water in a toilet. Some growers place a second tube near
the top of the container which they use as an overflow drain.
Another system uses a reservoir above the growing container
level. A water timing valve or solenoid valve keeps the water in the
reservoir most of the time. When the valve opens, the water fills the
growing containers as well as a central chamber which are both at
the same height. The growing chambers and the central chamber
are attached to each other. The water level is regulated by a float
valve and sump pump. When the water level reaches a certain
height, near the top of the pots, the sump pump automatically turns
on and the water is pumped back up to the reservoir.
One grower used a kiddie pool, timer valve, flower pots, a rais-
ed reservoir and sump pump. He placed the containers in the kiddie
pool along with the sump pump and a float valve. When the timer
valve opened, the water rushed from the tank to the kiddie pool,
flooding the containers. The pump turned on when the water was
twb inches from the top of the containers and emptied the pool.
Only when the valve reopened did the plants receive more water.
With this system, growers have a choice of mediums, including
sand, gravel, lava, foam or chopped-up rubber. Vermiculite,
perlite, and styrofoam are too light to use. The styrofoam and
perlite float, and the vermiculite becomes too soggy.
The plants' water needs to increase during the lighted part of
the daily cycle, so the best time to water is as the light cycle begins.
If the medium does not hold enough moisture between waterings,
the frequency of waterings is increased.
There are a number of companies which manufacture flood
systems. Most of the commercially made ones work well, but they
tend to be on the expensive side. They are convenient though.
The Drip System

Years ago, the most sophisticated commercial greenhouses
used drip emitter systems which were considered exotic and
sophisticated engineering feats. These days, gardeners can go to any
well-equipped nursery and find all of the materials necessary to
design and build the most sophisticated drip systems. These units
consist of tubing and emitters which regulate the amount of water
delivered to each individual container. Several types of systems can
he designed using these devices.
The easiest system to make is a non-return drain unit. The
plants are watered periodically using a diluted nutrient solution. Ex-
cess water drains from the containers and out of the system. This
System is only practical when there is a drain in the growing area. If

 

each container has a growing tray to catch excess water and the
water control valve is adjusted closely, any excess water can be held
in the tray and eventually used by the plant or evaporated. Once a
gardener gets the hang of it, matching the amount of water
delivered to the amount needed is easy to do.
One grower developed a drip emitter system which re-uses the
water by building a wooden frame using 2 x 4's and covering it with
corrugated plastic sheeting. She designed it so that there was a slight
slope. The containers were placed on the corrugated plastic, so the
water drained along the corrugations into a rain drainage trough,
which drained into a 2 or 3 gallon holding tank. The water was
pumped from the holding tank back to the reservoir. The water was
released from the reservoir using a timer valve.
Growers make sure to use self-cleaning drip emitters so that
they do not clog with salt deposits. About a gallon every six hours
during daylight hours is pumped. Drip emitters can be used with
semiporous mediums such as ceramic beads, lava, gravel, sand or
periite-vermiculite-styrofoam mixtures.
Aerated Water

The aerated water system is probably the most complex of the
hydroponic systems because it allows the least margin for error. It
should only be used by growers with previous hydroponic ex-
perience. The idea of the system is that the plant can grow in water
as long as the roots receive adequate amounts of oxygen. To pro-
vide the oxygen, an air pump is used to oxygenate the water through
bubbling and also by increasing the circulation of the water so that
there is more contact with air. The plants can be grown in in-
dividual containers, each with its own bubbler or in a single flooded
unit in which containers are placed. One grower used a vinyl-
covered tank he constructed. He placed individual containers that
he made into the tank. His containers were made of heavy-duty
nylon mesh used by beermakers for soaking hops. This did not pre-
vent water from circulating around the roots.
Aerated water systems are easy to build. A small aquarium air
pump supplies all the water that is required. An aerator should be
connected to the end and a clear channel made in the container for
the air. The air channel allows the air to circulate and not disturb
the roots. Gravel, lava, or ceramic is used.
Nutrient Film Technique

The nutrient film technique is so named because the system
creates a film of water that is constantly moving around the roots
This technique is used in many commercial greenhouses to cultivate ~
fast growing vegetables such as lettuce without any medium. The
plants are supported by collars which hold them in place. This
method is unfeasible for marijuana growers. However, it can be
modified a bit to create an easy4o-care-for garden. Nursery sup-
pliers sell water mats, which disperse water from a soaker hose to a
nylon mat. The plants grow in bottomless containers which sit on
the mat. The medium absorbs water directly from the mat. In order

 

to hold the medium in place, it is placed in a nylon net bag in the
container.

Chapter Ten

Growing in the Ground

Some growers have the opportunity to grow plants directly in
the ground. Many greenhouses are built directly over the earth.
Growing directly in the soil has many advantages over container
growing. A considerable amount of labor may be eliminated
because there is no need to prepare labor-intensive containers with
expensive medium. Another advantage is that the plants' needs are
met more easily.
Before using any greenhouse soil, it is necessary to test it. The
pH and fertility of soils vary so much that there are few generaliza-
tions that can be made about them.
The most important quality of any soil is its texture. Soils
which drain well usually are composed of particles of varying size.
This creates paths for water to flow and also allows air pockets to
remain even when the soil is saturated.
Soils composed of very fine particles, such as mucks and clay,
do not drain well. Few air particles are trapped in these soils when
they are saturated. When this happens, the roots are unable to ob-
tain oxygen and they weaken when they are attacked by anaerobic
bacteria. These soils should be adjusted with sand and organic mat-
ter which help give the medium some porosity. Materials suitable
for this include sand, compost, composted manure, as well as
perlite, lava, gravel, sphagnum moss, styrofoam particles and foam
particles.
Low lying areas may have a very high water table so that the
soils remain saturated most of the time. One way to deal with this
problem is to create a series of mounds or raised beds so that the
roots are in ground at higher level than the floor level.
Once soil nutrient values are determined, adjustments can be
made in the soil's fertility. For marijuana, the soil should test high
in total Nitrogen, and the medium should test high in Phosphorous
and Potassium. This is covered in subsequent chapters.

to Growers use several methods to prepare the soil. Some prefer
till the whole area using either a fork, a roto-tiller or a small trac-
tor and plow. The marijuana plant grows both vertical and horizon-
tal roots. The horizontal roots grow from the surface to a depth of
9-18 inches depending on the soil's moisture. They grow closer to I
the surface of moist soils. The vertical root can stretch down several
feet in search of water. In moist soils, the vertical roots may be
short, even stunted.
Soil with loose texture, sandy soils, and soils high in organic
matter may have adequate aeration, porosity, and space for roots
and may not have to be tilled at all. Most soils should be dug to a
depth of 6-9 inches. The tighter the soil's texture, the deeper it
should be tilled.

 

If the soil is compacted, it is dug to a depth of two feet. This
can be done by plowing and moving the soil in alternate rows and
then plowing the newly uncovered soil. Soil texture adjustors such
as gypsum are added to the bottom layer of the soil as well as the
top layer, but soil amendments such as fertilizers or compost are
added only to the top layer, where most of the plant's roots are.
Then the soil is moved back into the troughs and the alternate rows
are prepared the same way.
A variation of this technique is the raised bed. First, the whole
area is turned, and then aisles are constructed by digging out the
pathways and adding the material to the beds. With the addition of
organic soil amendments, the total depth of prepared soil may
stretch down 18 inches.
Some growers use planting holes rather than tilling the soil. A
hole ranging between 1 and 3 feet wide and 1 and 3 feet deep is
dug at each space where there is to be a plant. The digging can be
facilitated using a post hole digger, electric shovel, or even a small
backhoe or power hole digger. Once the hole is dug the soil is ad-
justed with amendments or even replaced with a mix.
No matter how the soil is prepared, the groundwater level and
the permeability of the lower layers is of upmost importance. Areas
with high water tables, or underlying clay or hardpan will not drain
well. In either case the garden should be grown in raised beds which
allow drainage through the aisles and out of the growing area,
rather than relying on downward movement through soil layers.
Soils in used greenhouses may be quite imbalanced even if the
plants were growing in containers. The soil may have a buildup of
nutrient salts, either from runoff or direct application, and
pesticides or herbicides may be present. In soils with high water
tables the nutrients and chemicals have nowhere to go, so they
dissolve and spread out horizontally as well as vertically, con-
taminating the soil in surrounding areas.
Excess salts can be flushed from the soil by flooding the area
with water and letting it drain to the water table. In areas with high
water tables, flushing is much more difficult. Trenches are dug
around the perimeter of the garden which is then flooded with
nutrient-free water. As the water drains into the trenches, it is
removed with a pump and transported to another location.
Pesticides and herbicides may be much more difficult to
remove. Soils contaminated with significant amounts of residues
may be unsuitable for use with material to be ingested or inhaled.
Instead, the garden should be grown in containers using non-
indigenous materials.
Usually plants are sexed before they are planted in the ground.
If the soil showed adequate nutrient values no fertilizer or side
dressing will be required for several months.
Several growers have used ingenious techniques to provide
their gardens with earthy environments. One grower in Oregon
chopped through the concrete floor of his garage to make planting
holes. The concrete had been poured over sub-soil so he dug out the
holes and replaced the sub-soil with a mixture of composted

 

manure, vermiculite, perlite, worm castings, and other organic in
gredients. He has been using the holes for several years. After
several crops, he redigs the holes and adds new ingredients to the
mix.
A grower in Philadelphia lived in a house with a backyard
which was cemented over. He constructed a raised bed over the con-
crete using railroad ties and filled it with a rich topsoil and com
posted manure mixture, then built his greenhouse over that. The
growing bed is about 15 inches deep and the grower reports incredi-
ble growth rates.

PART III.

Limiting Factors

There are five factors that can promote or limit plant growth.
Each may be a weak link in a chain and the plant can grow no faster
than the weakest link allows.
Light, C02, temperature, nutrients, and water are all needed
by the plant for it to carry on its life processes.
In an indoor environment, it is up to the gardener to make sure
that all of these conditions are met adequately so that the plant can
grow as quickly and healthily as possible.

Chapter Eleven

Lighting and Lights

Green plants use light for several purposes. The most amazing
thing that they do with it is to use the energy contained in light to
make sugar from water (H20) and carbon dioxide (C02). This pro-
cess is called photosynthesis and it provides the basic building block
for most life on Earth. Plants convert the sugars they make into
starches and then into complex molecules composed of starches,
such as cellulose. Amino acids, the building blocks of all proteins,
are formed with the addition of nitrogen atoms.
Plants also use light to regulate their other life processes. As we
mentioned earlier, marijuana regulates its flowering based on the
number of hours of uninterrupted darkness. (See Chapter 25,
Flowering)
Sunlight is seen as white light, but is composed of a broad band
of colors which cover the optic spectrum. Plants use red and blue
light most efficiently for photosynthesis and to regulate other pro-
cesses. However, they do use other light colors as well for
photosynthesis. In fact, they use every color except green, which
they reflect back. (That is why plants appear green; they absorb all
the other spectrums except green.) In controlled experiments, plants
respond more to the total amount of light received than to the spec-
trums in which it was delivered.
The best source of light is the sun. It requires no expense, no
electricity, and does not draw suspicion. It is brighter than artificial
lighting and is self-regulating. Gardeners can use the sun as a
Primary source of light if they have a large window, skylight,

 

translucent roof, enclosed patio, roof garden, or greenhouse. These
gardens may require some supplemental lighting, especially if the
light enters from a small area such as a skylight, in order to fill a
large area.
It is hard to say just how much supplemental light a garden
needs. Bright spaces which are lit from unobstructed overhead light
such as a greenhouse or a large southern window need no light dur-
ing the summer but may need artificial light during the winter to
supplement the weak sunlight or overcast conditions. Spaces receiv-
ing indirect sunlight during the summer need some supplemental
lighting.
Light requirements vary by variety. During the growth cycle,
most varieties will do well with 1000-1500 lumens per square foot
although the plants can use more lumens, up to 3000, efficiently.
Equatorial varieties may develop long internodes (spaces on the
stem between the leaves) when grown under less than bright condi-
tions. During flowering, indica varieties can mature well on 2000
lumens. Equatorial varieties require 2500-5000 lumens. Indica-
sativa F1 (first generation) hybrids usually do well on 2500-3000
lumens.
Some light meters have a foot-candle readout. Thirty-five
millimeter cameras that have built-in light meters can also be used.
In either case, a sheet of white paper is placed at the point to be
measured so it reflects the light most brilliantly. Then the meter is
focused entirely on the paper.
The camera is set for ASA 100 film and the shutter is set for 1/60
second. A 50 mm or "normal" lens is used. Using the manual
mode, the camera is adjusted to the correct f-stop. The conversion
chart, 10-1, shows the amount of light hitting the paper.
Most growers, for one reason or another, are not able to use
natural light to grow marijuana. Instead, they use artificial lights to
provide the light energy which plants require to photosynthesize,
regulate their metabolism, and ultimately to grow. There are a
number of sources of artificial lighting. Cultivators rarely use in-
candescent or quartz halogen lights. They convert only about l0%
of the energy they use to light and are considered inefficient.
CHART 10-1: FOOTCANDLES
1/60 Second, ASA 100 1/125 Second ASA 100
F-Stop Footcandles F-Stop Footcandles
f.4 64 f.4 126
f.5.6 125 f.5.6 250
f.8 250 f.8 500
f.11 500 f.11 1000
f.16 1000 f.16 2000
f.22 2000 f.22 4000

 

On some cameras it is easier to adjust the shutter speed, keeping the f. stop
set at f.4 (at ASA 100):

Shutter

 

Speed Footcandles
1/60 64
1/125 125
1/250 250
1/500 500
1/1000 1000
1/2000 2000
FLUORESCENT TUBES

 

Growers have used fluorescent tubes to provide light for many
years. They are inexpensive, are easy to set up, and are very effec-
tive. Plants grow and bud well under them. They are two to three
times as efficient as incandescents. Until recently, fluorescents came
mostly in straight lengths of 2, 4, 6, or 8 feet, which were placed in
standard reflectors. Now there are many more options for the
fluorescent user. One of the most convenient fixtures to use is the
screw-in converter for use in incandescent sockets, which come with
8 or 12 inch diameter circular fluorescent tubes. A U-shaped 9 inch
screw-in fluorescent is also available. Another convenient fixture is
the "light wand", which is a 4 foot, very portable tube. It is not
saddled with a cumbersome reflector.
Fluorescents come in various spectrums as determined by the
type of phosphor with which the surface of the tube is coated. Each
phosphor emits a different set of colors. Each tube has a spectrum
identification such as "warm white", "cool white", "daylight", or
"deluxe cool white" to name a few. This signifies the kind of light
the tube produces. For best results, growers use a mixture of tubes
which have various shades of white light. One company manufac-
tures a fluorescent tube which is supposed to reproduce the sun's
spectrum. It is called Vita-Lite and works well. It comes in a more
efficient version, the "Power Twist", which uses the same amount
of electricity but emits more light because it has a larger surface
area.
"Gro-Tubes" do not work as well as regular fluorescents even
though they produce light mainly in the red and blue spectrums.
They produce a lot less light than the other tubes.
To maintain a fast growing garden, a minimum of 20 watts of
fluorescent light per square foot is required. As long as the plants'
other needs are met, the more light that the plants receive, the faster
and bushier they will grow. The plants' buds will also be heavier
and more developed. Standard straight-tubed fluorescent lamps use
8-10 watts per linear foot. To light a garden, 2 tubes are required
for each foot of width. The 8 inch diameter circular tubes use 22
watts, the 12 inch diameter use 32 watts. Using straight tubes, it is
possible to fit no more than 4 tubes in each foot of width because of
the size of the tubes. A unit using a combination of 8 and 12 inch
circular tubes has an input of 54 watts per square foot.
Some companies manufacture energy-saving electronic ballasts
designed for use with special fluorescent tubes. These units use 39%
less electricity and emit 91 % of the light of standard tubes. For in-

 

stance an OptimizerÆ warm white 4 foot tube uses 28 watts and
emits 2475 lumens.
Both standard and VHO ballasts manufactured before 1980
are not recommended. They were insulated using carcinogenic
PCB's and they are a danger to your health should they leak.
The shape of the fluorescent reflector used determines, to a
great extent, how much light the plants receive. Fluorescent tubes
emit light from their entire surface so that some of the light is
directed at the reflector surfaces. Many fixtures place the tubes very
Close to each other so that only about 40% of the light is actually
transmitted out of the unit. The rest of it is trapped between the
tubes or between the tubes and the reflector. This light may as well
not be emitted since it is doing no good.
A better reflector can be constructed using a wooden frame.
Place the tube holders at equal distances from each other at least 4
inches apart. This leaves enough space to construct small mini-
reflectors which are angled to reflect the light downward and to
separate the light from the different tubes so that it is not lost in
crosscurrents. These mini-reflectors can be made from cardboard
or plywood and painted white. The units should be no longer than
2 feet wide so that they can be manipulated easily. Larger units
are hard to move up and down and they make access to the garden
difficult, especially when the plants are small, and there is not much
vertical space. The frame of the reflector should be covered with
reflective material such as aluminum foil so that all of the light is
directed to the garden. Fluorescent lights should be placed about
2-4 inches from the tops of the plants.
Growers sometimes use fluorescent lights in innovative ways to
supplement the main source of light. Lights are sometimes placed
along the sides of the garden or in the midst of it. One grower used
light wands which he hung vertically in the midst of the garden.
'Ibis unit provided light to the lower parts of the plants which are
often shaded. Another grower hung a tube horizontally at plant
level between each row. He used no reflector because the tube shin-
ec' on the plants from every angle. Lights can be hung at diagonal
angles to match the different plants' heights.

 

 

VERY HIGH OUTPUT (VHO) FLUORESCENTS

 

Standard fluorescents use about 10 watts per linear foot-a 4

foot fluorescent uses 40 watts, an 8 footer 72 watts. VHO tubes use
about three times the electricity that standard tubes use, or about
o 215 watts for an 8 foot tube, and they emit about 2 times the

light. While they are not quite as efficient as a standard tube, they
are often more convenient to use. Two tubes per foot produce the
equivalent electricity of S standard tubes. Only one tube per foot is

 

needed and two tubes emit a v&y bright light. The banks of tubes
are eliminated.
VHO tubes come in the same spectrums as standards. They re-
quire different ballasts than standards and are available at commer-
vial lighting companies.
METAL HALIDE LAMPS

Metal halide lamps are probably the most popular lamp used
for growing. These are the same type of lamp that are used out-
doors as streetlamps or to illuminate sports events. They emit a
white light. Metal halide lamps are very convenient to use. They
come ready to plug in. The complete unit consists of a lamp (bulb),
fixture (reflector) and long cord which plugs into a remote ballast.
The fixture and lamp are lightweight and are easy to hang. Only one
chain or rope is needed to suspend the fixture, which takes up little
space, making it easy to gain access to the garden.
In an unpublished, controlled experiment it was observed that
marijuana plants responded better to light if the light came from a
single point source such as a metal halide, rather than from emis-
sions from a broad area as with fluorescents. Plants growing under
metal halides develop quickly into strong plants. Flowering is pro-
fuse, with heavier budding than under fluorescents. Lower leaf
development was better too, because the light penetrated the top
leaves more.
Metal halide lamps are hung in two configurations: vertical
and horizontal. The horizontal lamp easily focuses at a higher per-
cent of light on the garden, but it emits 10% less light. Most
manufacturers and distributors sell vertically hanging metal halides.
However, it is worth the effort to find a horizontal unit.
In order for a vertical hanging metal halide lamp to deliver
light to the garden efficiently, the horizontal light that it is emitting
must be directed downward or the halide must be placed in the
midst of the garden. It only becomes practical to remove the reflec-
tor and let the horizontally directed light radiate when the plants
have grown a minimum of six feet tall. Reflectors for vertical lamps
should be at least as long as the lamp. If a reflector does not cover
the lamp completely, some of the light will be lost horizontally.
Many firms sell kits with reflectors which do not cover the whole
lamp.
Reflectors can be modified using thin gauge wire such as
poultry wire and aluminum foil. A h6le is cut out in the middle of
the chicken wire frame so that it fits over the wide end of the reflec-
tor. Then it is shaped so that it will distribute the light as evenly as
possible. Aluminum foil is placed over the poultry wire. (One
grower made an outer frame of 1 x 2's which held the poultry wire,
metal halide, and foil).
Metal halide lamps come in 400, 1000 and 1500 watt sizes. The
1500 watt lamps are not recommended because they have a much
shorter life than the other lamps. The 400 watt lamps can easily il-
luminate a small garden S x 5 feet or smaller. These are ideal lights
for a small garden. They are also good to brighten up dark spots in

 

the garden.
In European nurseries, 400 watt horizontal units are standard.
They are attached to the ceiling and placed at even 5 foot intervals
so that light from several lamps hits each plant. Each lamp beam
diffuses as the vertical distance from the plants may be 6-8 feet, but
no light is lost. The beams overlap. No shuttle type device is re-
quired. The same method can be used with horizontal 1000 watt
lamps and 8 foot intervals. Vertical space should be at least 12 feet.
HIGH PRESSURE SODIUM VAPOR LAMPS

 

Sodium vapor lamps emit an orange or amber-looking light.
They are the street lamps that are commonly used these days. These
lights look peculiar because they emit a spectrum that is heavily
concentrated in the yellow, orange, and red spectrums with only a
small amount of blue. They produce about 15% more light than
metal halides. They use the same configuration as metal halides:
lamp, reflector, and remote ballast.
Growers originally used single sodium vapor lamps primarily
for flowering because they thought that if the extra yellow and
orange light was closer to the sun's spectrum in the fall, when the
amount of blue light reaching Earth was limited, the red light would
increase flowering or resin production. In another unpublished con-
trolled experiment, a metal halide lamp and a sodium vapor lamp
were used as the only sources of light in 2 different systems. The
garden under the metal halide matured about a week faster than the
pyden under the sodium vapors. Resin content seemed about the
same Other growers have reported different results. They claim
Jilat the sodium vapor lamp does increase THC and resin produc-
Uon Plants can be grown under sodium vapor lights as the sole
'ource of illumination.
Many growers use sodium vapor lamps in conjunction with
metal halides; a typical ratio is 2 halides to 1 sodium. Some growers
use metal halides during the growth stages but change to sodium
vapor lamps during the harvest cycle. This is not hard to do since
o both lamps fit in the same reflector. The lamps use different
ballasts.
High pressure sodium vapor lamps come in 400 and 1000 watt
configurations with remote ballasts designed specifically for
culitivation. Smaller wattages designed for outdoor illumination are
available from hardware stores. The small wattage lamps can be us-
ed for brightening dark areas of the garden or for hanging between
the rows of plants in order to provide bright light below the tops.
ACCESSORIES

 

One of the most innovative accessories for lighting is the
"Solar Shuttle' 'Æ and its copies. This device moves a metal halide or
sodium vapor lamp across a track 6 feet or longer. Because the
lamp is moving, each plant comes directly under its field several
times during the growing period. Instead of plants in the center

 

receiving more light than those on the edge, the light is more equally
distributed. This type of unit increases the total efficiency of the
light. Garden space can be increased by I 5-20% or the lamp can be
used to give the existing garden more light.
Other units move the lamps over an arc path. The units take
various amounts of time to complete a journey - from 40 seconds
upward.
ELECTRICITY AND LIGHTING

 

At 110-120 volts, a 1000 watt lamp uses about 8.7 amps (watts
divided by volts equals amps). Including a 15% margin for safety it
can be figured as 10 amps. Many household circuits are rated for 20
or 30 amps. Running 2 lights on a twenty amp circuit taxes it to
capacity and is dangerous. If more electricity is required than can be
safely supplied on a circuit, new wiring can be installed from the
fusebox.
All electrical equipment should be grounded.
Some growers report that the electrical company's interest was
aroused, sometimes innocently, when their electric bill began to
spurt. After all, each hour a lamp is on it uses about 1 kilowatt
hour.

Chapter Twelve

Carbon Dioxide

Carbon dioxide (C02) is a gas which comprises about .03% or
(300 parts per million, "PPM") of the atmosphere. It is not
dangerous. It is one of the basic raw materials (water is the other)
required for photosynthesis. The plant makes a sugar molecule us-
ing light for energy, C02 which is pulled out of the air, and water,
which is pulled up from its roots.
Scientists believe that early in the Earth's history the at-
mosphere contained many times the amount of C02 it does today.
Plants have never lost their ability to process gas at these high rates.
In fact, with the Earth's present atmosphere, plant growth is
limited.
When plants are growing in an enclosed area, there is a limited
amount of C02 for them to use. When the C02 is used up, the
plant's photosynthesis stops. Only as more C02 is provided can the
plant use light to continue the process. Adequate amounts of C02
may be easily replaced in well-ventilated areas, but increasing the
amount of C02 to .2% (2000 PPM) or 6 times the amount usually
found in the atmosphere, can increase the growth rate by up to S
times. For this reason, many commercial nurseries provide a
C02-enriched area for their plants.
Luckily, C02 can be supplied cheaply. At the most organic
level, there are many metabolic processes that create C02. For ex-
ample, organic gardeners sometimes make compost in the
greenhouse. About 1/6 to º of the pile's starting wet weight is con-
verted to C02 so that a 200 pound pile contributes 33-50 pounds of

 

carbon to the gas. Carbon makes up about 27% of the weight and
volume of the gas and oxygen makes up 73%, so that the total
amount of C02 created is 122 to 185 pounds produced over a 30 day
period.
Brewers and vintners would do well to ferment their beverages
in the greenhouse. Yeast eat the sugars contained in the fermenta-
tion mix, releasing C02 and alcohol. The yeast produce quite a bit
of C02 when they are active.
One grower living in a rural area has some rabbit hutches in his
greenhouse. The rabbits use the oxygen produced by the plants, and
in return, release C02 by breathing. Another grower told me that he
is supplying his plants with C02 by spraying them periodically with
seltzer (salt-free soda water), which is water with C02 dissolved. He
claims to double the plants' growth rate. This method is a bit expen-
sive when the plants are large, but economical when they are small.
A correspondent used the exhausts from his gas-fired water
heater and clothes dryer. To make the area safe of toxic fumes that
might be in the exhaust, he built a manually operated shut-off valve
so that the spent air could be directed into the growing chamber or
up a flue. Before he entered the room he sent any exhausts up the
flue and turned on a ventilating fan which drew air out of the room.
Growers do not have to become brewers, rabbit farmers, or
spray their plants with Canada Dry. There are several economical
and convenient ways to give the plants adequate amounts of C02:
using a C02 generator, which burns natural gas or kerosene, using a
C02 tank with regulator, or by evaporating dry ice.
To find out how much C02 is needed to bring the growing area
to the ideal 2000 PPM, multiply the cubic area of the growing room
(length x width x height) by .002. The total represents the number
of square feet of gas required to reach optimum C02 range. For in-
stance, a room 13' x 18' x 12' contains 2808 cubic feet: 2808 x .002
equals 5.6 cubic feet of C02 required. The easiest way to supply the
gas is to use a C02 tank. All the equipment can be built from parts
available at a welding supply store or purchased totally assembled
from many growing supply companies. Usually tanks come in 20
and 50 pound sizes, and can be bought or rented. A tank which
holds 50 pounds has a gross weight of 170 pounds when filled.

A grow room of 500 cubic feet requires 1 cubic foot of C02
A grow room of 1000 cubic feet requires 2 cubic feet of C02
A grow room of 5000 cubic feet requires 10 cubic feet of C02
A grow room of 10,000 cubic feet requires 20 cubic feet of C02

To regulate dispersal of the gas, a combination flow
meter/regulator is required. Together they regulate the flow bet-
ween 10 and 50 cubic feet per hour. The regulator standardizes the
pressure and regulates the number of cubic feet released per hour.
A solenoid valve shuts the flow meter on and off as regulated by a
multicycle timer, so the valve can be turned on and off several times
each day. If the growing room is small, a short-range timer is need-
ed. Most timers are calibrated in hour increments, but a short-

 

range timer keeps the valve open only a few minutes.
To find out how long the valve should remain open, the
number of cubic feet of gas required (in our example 5.6 cubic feet)
is divided by the flow rate. For instance, if the flow rate is 10 cubic
feet per hour, 5.6 divided by 10 = .56 hours or 33 minutes (.56 x
60 minutes = 33 minutes). At 30 cubic feet per hour, the number of
minutes would be .56 divided by 30 x 60 minutes = 11.2 minutes.
The gas should be replenished every two hours in a warm, well-
lit room when the plants are over 3 feet high if there is no outside
ventilation. When the plants are smaller or in a moderately lit
room, they do not use the C02 as fast. With ventilation the gas
should be replenished once an hour or more frequently. Some
growers have a ventilation fan on a timer in conjunction with the
gas. The fan goes off when the gas is injected into the room. A few
minutes before the gas is injected in the room, the fan starts and
removes the old air. The gas should be released above the plants
since the gas is heavier than air and sinks. A good way to disperse
the gas is by using inexpensive "soaker hoses", sold in plant
nurseries. These soaker hoses have tiny holes in them to let out the
C02.
The C02 tank is placed where it can be removed easily. A hose
is run from the regulator unit (where the gas comes out) to the top
of the garden. C02 is cooler and heavier than air and will flow
downward, reaching the top of the plants first.
Dry ice is C02 which has been cooled to - 109 degrees, at
which temperature it becomes a solid. It costs about the same as the
gas in tanks. It usually comes in 30 pound blocks which evaporate
at the rate of about 7% a day when kept in a freezer. At room
temperatures, the gas evaporates considerably faster, probably sup-
plying much more C02 than is needed by the plants. One grower
worked at a packing plant where dry ice was used. Each day he took
home a couple of pounds, which fit into his lunch pail. When he
came home he put the dry ice in the grow room, where it evaporated
over the course of the day.
Gas and kerosene generators work by burning hydrocarbons
which release heat and create C02 and water. Each pound of fuel
burned produces about 3 pounds of CO2, 1 pounds of water and
about 21,800 BTU's (British Thermal Units) of heat. Some gases
and other fuels may have less energy (BTU's) per pound. The fuel's
BTU rating is checked before making calculations.
Nursery supply houses sell C02 generators especially designed
for greenhouses, but household style kerosene or gas heaters are
also suitable. They need no vent. The C02 goes directly into the
room's atmosphere. Good heaters burn cleanly and completely,
leaving no residues, creating no carbon monoxide (a colorless,
odorless, poisonous gas). Even so, it is a good idea to shut the
heater off and vent the room before entering the space.
If a heater is not working correctly, most likely it burns the fuel
incompletely, creating an odor. More expensive units have pilots
and timers; less expensive models must be adjusted manually.
Heaters with pilots can be modified to use a solenoid valve and

 

timer.
At room temperature, one pound of C02 equals 8.7 cubic feet.
It takes only of a pound of kerosene (5.3 ounces) to make a
pound of C02. To calculate the amount of fuel required, the
number of cubic feet of gas desired is divided by 8.7 and multiplied
by .33. In our case, 5.6 cubic feet divided by 8.7 times .33 equals .21
pounds of fuel. To find out how many ounces this is, multiply .21
times 16 (number of ounces in a pound) to arrive at a total of 3.3
ounces, a little less than half a cup (4 ounces).

6/10ths ounce produces 1 cubic foot of C02
1.2 ounces produce 2 cubic feet of C02
3 ounces produce 5 cubic feet of C02
6 ounces produce 10 cubic feet of C02
To find out fuel usage, divide the number of BTU's produced
by 21,800. If a generator produces 12,000 BTU's an hour, it is using
12,000 divided by 21,800 or about .55 pounds of fuel per hour.
However only .21 pounds are needed. To calculate the number of
minutes the generator should be on, the amount of fuel needed is
divided by the flow rate and multiplied by 60. In our case, .21
(amount of fuel needed) divided by .55 (flow rate) multiplied by 60
equals 22.9 minutes.
The C02 required for at least one grow room was supplied us-
ing gas lamps. The grower said that she thought it was a shame that
the fuel was used only for the C02 and thought her plants would
benefit from the additional light. She originally had white gas lamps
spaced evenly throughout the garden. She replaced them after the
first crop with gas lamps all hooked up to a central LP gas tank.
She only had to turn the unit on and light the lamps each day. It
shut itself off. She claims the system worked well.
C02 should be replenished every 3 hours during the light cycle,
since it is used up by the plants and leaks from the room into the
general atmosphere. Well-ventilated rooms should be replenished
more often. It is probably more effective to have a generator or
tank releasing C02 for longer periods at slower rates than for
shorter periods of time at higher rates.

Chapter Thirteen

Temperature

Marijuana plants are very hardy and survive over a wide range
of temperatures. They can withstand extremely hot weather, up to
120 degrees, as long as they have adequate supplies of water. Can-
nabis seedlings regularly survive light frost at the beginning of the
season.
Both high and low temperatures slow marijuana's rate of
metabolism and growth. The plants function best in moderate
temperatures - between 60 and 85 degrees. As more light is
available, the ideal temperature for normal plant growth increases.
If plants are given high temperatures and only moderate light, the
stems elongate. Conversely, strong light and low temperatures

 

decrease stem elongation. During periods of low light, strong
elongation is decreased by lowering the temperature. Night
temperatures should be 10-15 degrees lower than daytime
temperatures.
Temperatures below 50 degrees slow growth of most varieties.
When the temperature goes below 40 degrees, the plants may ex-
perience some damage and require about 24 hours to resume
growth. Low nighttime temperatures may delay or prevent bud
maturation. Some equatorial varieties stop growth after a few 40
degree nights.
A sunny room or one illuminated by high wattage lamps heats
up rapidly. During the winter the heat produced may keep the room
comfortable. However the room may get too warm during the sum-
mer. Heat rises, so that the temperature is best measured at the
plants' height. A room with a 10 foot ceiling may feel uncomfor-
tably warm at head level but be fine for plants 2 feet tall.
If the room has a vent or window, an exhaust fan can be used
to cool it. Totally enclosed spaces can be cooled using a water con-
ditioner which cools the air by evaporating water. If the room is lit
entirely by lamps, the day/night cycle can be reversed so that the
heat is generated at night, when it is cooler out.
Marijuana is low-temperature tolerant. Outdoors, seedlings
sometimes pierce snow cover, and older plants can withstand short,
light frosts. Statistically, more males develop in cold temperatures.
However, low temperatures slow down the rate of plant
metabolism. Cold floors lower the temperature in containers and
medium, slowing germination and growth. Ideally, the medium
temperature should be 70 degrees. There are several ways to warm
the medium. The floor can be insulated using a thin sheet of
styrofoam, foam rubber, wood or newspaper. The best way to in-
sulate a container from a cold floor is to raise the container so that
there is an air space between it and the floor.
Overhead fans, which circulate the warm air downward from
the top of the room also warm the medium.
When the plants' roots are kept warm, the rest of the plant can
be kept cooler with no damage. Heat cables or heat mats, which use
small amounts of electricity, can be used to heat the root area.
These are available at nursery supply houses.
When watering, tepid water should be used. Cultivators using
systems that recirculate water can heat the water with a fish tank
heater and thermostat. If the air is cool, 45-60 degrees, the water
can be heated to 90 degrees. If the air is warm, over 60 degrees, 70
degrees for the water is sufficient. The pipes and medium absorb
the water down a bit before it reaches the roots.
Gardens using artificial lighting can generate high air
temperatures. Each 1000 watt metal halide and ballast emits just a
little less energy than a 10 amp heater. Several lights can raise the
temperature to an intolerable level. In this case a heat exchanger is
required. A venting fan or misters can be used to lower
temperatures. Misters are not recommended for use around lights.
Greenhouses can also get very hot during the summer. If the

 

sun is very bright, opaquing paint may lower the amount of light
and heat entering the greenhouse. Fans and cooling mats also help.
Cooling mats are fibrous plastic mats which hold moisture. Fans
blow air through the mats which lowers the greenhouSC
temperature. They are most effective in hot dry areas. They are
available through nursery supply houses.

Chapter Fourteen

Air and Humidity

Besides temperature and C02 content, air has other qualities
including dust content, electrical charge and humidity.

 

Dust

"Dust" is actually composed of many different-sized solid and
liquid particles which float in the gaseous soup. The particles in-
clude organic fibers, hair, other animal and vegetable particles,
bacteria, viruses, smoke and odoriferous liquid particles such as
essential oils, and water-soluble condensates. Virtually all of the
particles have a positive electrical charge, which means that they are
missing an electron, and they float (due to electrical charge)
tbrough various passing gasses.
The dust content of the air affects the efficiency of the plant's
ability to photosynthesize. Although floating dust may block a
small amount of light, dust which has precipitated on leaves may
blcck large amounts. Furthermore, the dust clogs the pores through
which plants transpire. Dust can easily be washed off leaves using a
fme mist spray. Water must be prevented from touching and shat-
tering the hot glass of the lights.

 

Negative Ions

In unindustrialized verdant areas and near large bodies of
water, the air is negatively charged, that is, there are electrons
floating in the air unattached to atoms or molecules. In industrializ-
ed areas or very dry regions, the air is positively charged; there are
atoms and molecules missing electrons.
Some researchers claim that the air's electrical charge affects
plant growth (and also animal behavior). They claim that plants in a
positively charged environment grow slower than those in a
Regatively charged area.
. ,
Regardless of the controversy regarding growth and the air 5
electrical charge, the presence of negative ions creates some readily
observable effects. Odors are characteristic of positively charged
particles floating in the air. A surplus of negative ions causes the
particles to precipitate so that there are no odors. With enough
negative ions, a room filled with pungent, flowering sinsemilla is

 

odorless.
Spaces with a "surplus" negative ion charge have clean, fresh-
smelling air. Falling water, which generates negative ions,
characteristically creates refreshing air. Dust particles are
precipitated so that there are fewer bacteria and fungus spores
floating in the air, as well as much less dust in general. This lowers
chance of infection.
Many firms manufacture "Negative Ion Generators",
"Ionizers", and "Ion Fountains", which disperse large quantities
of negative ions into the atmosphere. These units are inexpensive,
safe and recommended for all growing areas. Ion generators
precipitate particles floating in the air. With most generators, the
precipitating particles land within a radius of two feet of the point
of dispersal, collecting quickly and developing into a thick film of
grime. Newspaper is placed around the unit so that the space does
not get soiled. Some newer units have a precipitator which collects
dust on a charged plate instead of the other surrounding surfaces.
This plate can be roughly simulated by grounding a sheet of
aluminum foil. To ground foil, either attach it directly to a metal
plumbing line or grounding box; for convenience, the foil can be
held with an alligator clip attached to the electrical wire, which is at-
tached to the grounding source. As the foil gets soiled, it is replac-
ed.

 

Humidity

Cannabis grows best in a mildly humid environment: a relative
humidity of 40-60 percent. Plants growing in drier areas may ex-
perience chronic wilt and necrosis of the leaf tips. Plants growing in
a wetter environment usually experience few problems; however,
the buds are more susceptible to molds which can attack a garden
overnight and ruin a crop.
Growers are rarely faced with too dry a growing area. Since the
space is enclosed, water which is evaporated or transpired by the
plants increases the humidity considerably. If there is no ventila-
tion, a large space may reach saturation level within a few days.
Smaller spaces usually do not have this buildup because there is
usually enough air movement to dissipate the humidity. The solu-
tion may be as easy as opening a window. A small ventilation fan
can move quite a bit of air out of a space and may be a convenient
way of solving the problem. Humidity may be removed using a
dehumidifier in gardens without access to convenient ventilation.
Dehumidifiers work the same way a refrigerator does except
that instead of cooling a space, a series of tubes is cooled causing at-
mospheric water to condense. The smallest dehumidifiers (which
can dry out a large space) use about 15 amps. Usually the
dehumidifier needs to run only a few hours a day. If the plant
regimen includes a dark cycle, then the dehumidifier can be run
when the lights are off, to ease the electrical load.

 

 

 

Air Circulation

A close inspection of a marijuana leaf reveals many tiny hairs
and a rough surface. Combined, these trap air and create a micro-
environment around the plant. The trapped air contains more
humidity and oxygen and is warmer, which differs significantly in
composition and temperature from the surrounding atmosphere.
The plant uses C02 so there is less left in the air surrounding the
leaf. Marijuana depends on air currents to move this air and renew
the micro-environment. If the air is not moved vigorously, the
growth rate slows, since the micro-environment becomes C02
depleted.
Plants develop firm, sturdy stems as the result of environmen-
tal stresses. Outdoors, the plants sway with the wind, causing tiny
breaks in the stem. These are quickly repaired by the plant's rein-
forcing the original area and leaving it stronger than it was original-
ly. Indoors, plants don't usually need to cope with these stresses so
their stems grow weak unless the plants receive a breeze or are
shaken by the stems daily.
A steady air flow from outdoor ventilation may be enough to
keep the air moving. If this is not available, a revolving fan placed
several feet from the nearest plant or a slow-moving overhead fan
can solve the problem. Screen all air intake fans to prevent pests.

Chapter Fifteen

pH and Water

The pH is the measure of acid-alkalinity balance of a solution.
It is measured on a scale of 0-14, with 0 being the most acid, 7 being
neutral, and 14 being most alkaline. Most nutrients the plants use
are soluble only in a limited range of acidity, between about 6 to
about 7, neutral. Should the water become too acid or alkaline,
the nutrients dissolved in the water precipitate and become
unavailable to the plants. When the nutrients are locked up, plant
growth is slowed. Typically, a plant growing in an environment
with a low pH will be very small, often growing only a few inches in
several months. Plants growing in a high pH environment will look
pale and sickly and also have stunted growth.
All water has a pH which can be measured using aquarium or
garden pH chemical reagent test kits or a pH meter. All of these
items are available at local stores and are easy to use. Water is pH-
adjusted after nutrients are added, since nutrients affect the pH.
Once the water is tested it should be adjusted if it does not fall
within the pH range of 6 to 7. Ideally the range should be about
6.2-6.8. Hydroponic supply companies sell measured adjusters
which are very convenient and highly recommended. The water-
nutrient solution can be adjusted using common household
chemicals. Water which is too acid can be neutralized using bicar-
bonate of soda, wood ash, or by using a solution of lime in the
medium.

 

Water which is too alkaline can be adjusted using nitric acid,
sulfuric acid, citric acid (Vitamin C) or vinegar. The water is ad-
justed using small increments of chemicals. Once a standard
measure of how much chemical is needed to adjust the water, the
process becomes fast and easy to do.
Plants affect the pH of the water solution as they remove
various nutrients which they use. Microbes growing in the medium
also change the pH. For this reason growers check and adjust the
pH periodically, about once every two weeks.
The pH of water out of the tap may change with the season so
it is a good idea to test it periodically.
Some gardeners let tap water sit for a day so that the chlorine
evaporates. They believe that chlorine is harmful to plants.
The pH of the planting medium affects the pH of the liquid in
solution. Medium should be adjusted so that it tests between
6.2-6.8. This is done before the containers are filled so that the
medium could be adjusted in bulk. Approximately 1-2 lbs. of
dolomitic limestone raises the pH of 100 gallons (4.5-9 grams per
gallon) of soil 1 point. Gypsum can be used to lower the pH of soil
or medium. Both limestone and gypsum have limited solubility.
There are many forms of limestone which have various effec-
tiveness depending on their chemistry. Each has a rating on the
package.

Chapter Sixteen
Nutrients

Marijuana requires a total of 14 nutrients which it obtains
through its roots. Nitrogen (N), Phosphorous (P), and Potassium
(K) are called the macro-nutrients because they are used in large
quantities by the plant. The percentages of N, P, and K are always
listed in the same order on fertilizer packages.
Calcium (Ca), sulfur (S), and magnesium (Mg) are also re-
quired by the plants in fairly large quantities. These are often called
the secondary nutrients.
Smaller amounts of iron (Fe), zinc (Zn), manganese (Mn),
boron (B), cobalt (Co), copper (Cu), molybdenum (Mo) and
chlorine (Cl) are also needed. These are called micro-nutrients.
Marijuana requires more N before flowering than later in its
cycle. When it begins to flower, marijuana's use of P increases.
Potassium requirements increase after plants are fertilized as a
result of seed production.
Plants which are being grown in soil mixes or mixes with
nutrients added such as compost, manure or time-release fertilizers
may need no additional fertilizing or only supplemental amounts if
the plants begin to show deficiencies.
The two easiest and most reliable ways to meet the plant's
needs are to use a prepared hydroponic fertilizer or an organic
water-soluble fertilizer. Hydroponic fertilizers are blended as com-
plete balanced formulas. Most non-hydroponic fertilizers usually
contain only the macronutrients, N, P and K. Organic fertilizers
such as fish emulsion and other blends contain trace elements which

 

are found in the organic matter from which they are derived.
Most indoor plant fertilizers are water-soluble. A few of them
are time-release formulas which are mixed into the medium as it is
being prepared. Plants grown in soil mixes can usually get along us-
ing regular fertilizers but plants grown in prepared soilless mixes
definitely require micronutrients.
As the seeds germinate they are given a nutrient solution high
in N such as a 20-10-10 or 17-10-12. These are just two possible
formulas; any with a high proportion of N will do.
Formulas which are not especially high in N can be used and
supplemented with a high N fertilizer such as fish emulsion (which
may create an odor) or the Sudbury XÆ component fertilizer which
is listed as 44-0-0. Urine is also very high in N and is easily absorb-
ed by the plants. It should be diluted to one cup urine per gallon of
water.
The plants should be kept on a high N fertilizer regimen until
they are put into the flowering regimen.
During the flowering cycle, the plants do best with a formula
lower in N and higher in P, which promotes bloom. A fertilizer
such as 5-20-10 or 10-19-12 will do. (Once again, these are typical
formulas, similar ones will do).
Growers who make their own nutrient mixes based on parts per
million of nutrient generally use the following formulas.

 

CHART 15-1: NUTRIENT/WATER SOLUTION IN PARTS PER MILLION (PPM)
N P K
Germination - 15 to 20 days 110-150 70-100 50-75
Fast Growth 200-250 60-80 150-200
Pre-Flowering 70-100 100-150 75-100
2 weeks before turning light down
Flowering 0-50 100-150 50-75
Seeding - fertilized flowers 100-200 70-100 100-150

 

 

Plants can be grown using a nutrient solution containing no N
for the last 10 days. Many of the larger leaves yellow and wither as
the N migrates from old to the new growth. The buds are less green
and have less of a minty (chlorophyll) taste.
Many cultivators use several brands and formulas of fertilizer.
They either mix them together in solution or switch brands each
feeding.
Plant N requirements vary by weather as well as growth cycle.
Plants growing under hot conditions are given 10-20% less N or
else they tend to elongate and to grow thinner, weaker stalks. Plants
in a cool or cold regimen may be given 10-20% more N. More N is
given under high light conditions, less is used under low light
conditions.
Organic growers can make "teas" from organic nutrients by
soaking them in water. Organic nutrients usually contain

 

micronutrients as well as the primary ones. Manures and blood
meal are among the most popular organic teas, but other organic
sources of nutrients include urine, which may be the best source for
N, as well as blood meal and tankage. Organic fertilizers vary in
their formulas. The exact formula is usually listed on the label.
Here is a list of common organic fertilizers which can be used
to make teas:

CHART 15-2: ORGANIC FERTILIZERS
Fertilizer N P K Remarks
Bloodmeal 15 1.3 .7 Releases nutrients easily
Cow manure 1.5 .85 1.75 The classic tea. Well-
(dried) balanced formula. Medium
availability.
Dried blood 13 3 0 Nutrients dissolve easier
than bloodmeal.
Chicken manure 3.5 1.5 .85 Excellent nutrients.
Wood ashes 0 1.5 7 Water-soluble. Very alkaline
except with acid wood such
as walnut.
Granite dust 0 0 5 Dissolves slowly
Rock phospate 0 33 0 Dissolves gradually.
(phosphorous)
Urine (human, .5 .003 .003 N immediately available.
fresh)

 

Commercial water-soluble fertilizers are available. Fish emul-
sion fertilizer comes in 5-1-1 and 5-2-2 formulas and has been used
by satisfied growers for years.
A grower cannot go wrong changing hydroponic
water/nutrient solutions at least once a month. Once every two
weeks is even better. The old solution could be measured, refor-
Inulated, supplemented and re-used; unless large amounts of fer-
tilizer are used, such as in a large commercial greenhouse, it is not
worth the effort. The old solution may have many nutrients left,
but it may be unbalanced since the plants have drawn specific
chemicals. The water can be used to water houseplants or an out-
door garden, or to enrich a compost pile.
Experienced growers fertilize by eyeing the plants and trying to
determine their needs when minor symptoms of deficiencies become
apparent. If the nutrient added cures the deficiency, the plant
usually responds in apparent ways within one or two days. First the
spread of the symptom stops. With some minerals, plant parts that
were not too badly damaged begin to repair themselves. Plant parts
which were slightly discolored may return to normal. Plant parts
which were severely damaged or suffered from necrosis do not
recover. The most dramatic changes usually appear in new growth.
These parts grow normally. A grower can tell just by plant parts
which part grew before deficiencies were corrected.
Fertilizers should be applied on the low side of recommended

 

rates. Overdoses quickly (within hours) result in wilting and then
death. The symptoms are a sudden wilt with leaves curled under. To
save plants suffering from toxic overdoses of nutrients, plain water
is run through systems to wash out the medium.
Gardens with drainage can be cared for using a method com-
mercial nurseries employ. The plants are watered each time with a
dilute nutrient/water solution, usually 20-25% of full strength. Ex-
cess water runs off. While this method uses more water and
nutrients than other techniqes, it is easy to set up and maintain.
When nutrient deficiencies occur, especially multiple or micro-
nutrient deficiencies, there is a good chance that the minerals are
locked up (precipitated) because of pH. Rather than just adding
more nutrients, the pH must be checked first. If needed, the pH
must be changed by adjusting the water.
If the pH is too high, the water is made a lower pH than it
would ordinarily be; if too low the water is made a higher pH. To
get nutrients to the plant parts immediately, a dilute foliar spray is
used. If the plant does not respond to the foliar spray, it is being
treated with the wrong nutrient.
NUTRIENTS

 

Nitrogen (N)

Marijuana uses more N than any other nutrient. It is used in
the manufacture of chlorophyll. N migrates from old growth to
new, so that a shortage is likely to cause first pale green leaves and
then the yellowing and withering of the lowest leaves as the nitrogen
travels to new buds. Other deficiency symptoms include smaller
leaves, slow growth and a sparse rather than bushy profile.
N-deficient plants respond quickly to fertilization. Within a
day or two, pale leaves become greener and the rate and size of new
growth increases. Good water-soluble sources of nitrogen include
most indoor and hydroponic fertilizers, fish emulsion, and urine,
along with teas made from manures, dried blood or