Table of Contents
Part I: Introduction
1. The history of cannabis 15
1.1. Preface 15
1.2. The journey 15
1.3. Cannabis in the Netherlands 16
2. Physiology of plants 19
2.1. Preface 19
2.2. Principles of growth 19
2.3. Osmotic processes 23
2.4. Intake and circulation of materials 26
2.5. Factors influencing the growth of plants 29
Part II: Necessities and climate control
3. Necessities and basic installations 30
3.1. Preface 30
3.2. The growing space 31
3.3. Shopping list 32
3.4. Growing space layout 35
4. Light 41
4.1. Preface 41
4.2. Choice of lamps 42
4.3. Using high-pressure gas lamps 46
4.4. Proper lighting for cannabis 47
5. Air 49
5.1. Preface 49
5.2. Influencing air quality 49
5.3. Relative humidity 53
5.4. Temperature 55
6. Water 57
6.1. Preface 57
6.2. Water quality 57
6.3. The irrigation system 64
Part III: Growing cannabis
7. Plant growth 70
7.1. Preface 70
7.2. Cloning hemp 70
7.3. The vegetative phase 77
7.4. The generative phase 79
7.5. Harvesting and drying 81
7.6. Skuff 83
7.7. Setting up the garden again 84
8. Diseases and insects 86
8.1. Preface 86
8.2. Diseases 87
8.3. Pests 90
8.4. Summary 96
Acidity - Defines the measure for the uptake of nutrient salts by the
plant. Acidity is indicated by the pH value.
A pH value of 5.8 is ideal for the cultivation of cannabis.
B - Abbreviation for boron, a material necessary in very small quantities for the growth of cannabis.
Blue light - Light given out by mercury-iodide lamps which is
necessary for the formation of chlorophyll in plants.
Blue light has a wavelength of approximately 445 nanometers
Ca - Abbreviation for calcium; necessary for osmotic processes in the plant
Chlorophyll - The official name for 'leaf-green'. Chlorophyll gives
the plant its green color,
and is important in the conversion of CO2 and H2O into glucose.
Clones - Weed-growers' jargon for cuttings.
CO2 - The chemical formula for carbondioxide; next to water, the most important basic material for the growth of plants.
C6H12O6 - Chemical formula for glucose, the basic material used by plants for growth and flowering.
Dark Part of photosynthesis. During response, the dark reaction, the
actual formation of glucose from water and
carbondioxide takes place.
Deficiency Plant disease brought on by the disease-application of too little of a certain fertilizing material.
EC - Electrical conductivity. The electrical conductivity standard of
water, which can be measured with an EC meter,
tells whether or not the composition of the fertilizer is correct
Fe - Abbreviation for iron; an element in the nutrient solution.
Generative phase - The flowering phase of plants. When cannabis is
cultivated indoors, this phase begins, at maximum,
one week to ten days after a clone with roots is planted, and continues, depending on the variety,
two to three months.
GH - Abbreviation for 'German hardness', a scale for the hardness of
(namely the quantity of calcium) indicated in degrees.
High- Cultivation under artificial light pressure makes use of
They give out the desired quantity of light with the desired wavelength.
(High-pressure sodium lamps - red light for growth, mercury-iodide lamps -blue light for the formation of chlorophyll.)
H2O - Chemical formula for water, consisting of two parts hydrogen(H), and one part oxygen (O).
Hygrometer - A meter with which the relative humidity can be established<P>
Hygrostat - An apparatus which maintains correct relative humidity. A good hygrostat keeps the relative humidity constant in a room.
Internode - The distance between the leaves and the tops of a plant.
When light only from the red spectrum is applied during the generative phase, the internodes become longer.
K - Abbreviation for potassium, which is, next to nitrogen and phosphate, one of the primary nutrients for plants.
Light Part of photosynthesis in which response photolysis takes
Photosynthesis also includes the dark response, in which the actual formation of glucose occurs.
Lumen - The international measure for luminosity from a light source.
Ma - Abbreviation for manganese, an element used in very small quantities by plants.
Membrane- Membrane allowing small molecules to pass through but not the larger ones.
Mg - Abbreviation for magnesium, an element plants need for the
build-up of chlorophyll, and for osmotic processes.
Micro-element - Nutrients the plant only barely needs; for example, copper and zinc.
Millisiemens- The international measure for electrical conductivity.
Nanometer - Measure of length used to express the wavelength of
Red light travels at a wavelength of approximately 650 nanometers(nm), blue light at approximately 450 nm.
A nanometer is one thousand millionth of a meter(10-8m).
NPK - Abbreviation for nitrogen (N),phosphate (P), and potassium(K), the three primary nutrients for plants.
Osmosis - The phenomenon in which water containing a dissolved
substance of a low concentration is absorbed
via a membrane into water which contains substances of higher concentrations (for example in plants).
Osmosis is very important to plants for sturdiness, and for the transport of water and nutrient materials.
Pressure is built up by osmosis, making the plant sturdy. If this pressure falls, the plant loses its sturdiness.
P - Abbreviation for phosphate, one of the three primary nutrients.
pH - The pH is a measure of the acidity of a solution (for example,
water with nutrients).
The pHscale goes from 0 to 14.
The lower the pH value, the more acidic the solution
Photolysis - Part of photosynthesis, in which water (H2O) is split up
into hydrogen (H), and oxygen (O).
This occurs during the light response.
Photosynthesis - The chemical process in plants, in which
carbondioxide and water are converted into glucose
by the influence of light energy
Phototropism- The inclination, which plants have, to grow towards light<P>
Physiology - The science of growth. (Plantphysiology is the science concerned with the growth and flowering of plants)
ppm - 'Parts per million'.
The amount of material in the air, of CO2, for example, is expressed not only in percent,
but also in ppm. 0.03% CO2 in the air is equivalent to 300 ppm.
Predator - A predator is an insect that protects plants against other insects such as spider mites, white flies, and thrips.
Red light - Light needed by plants in order to grow. Red light has a wavelength of approximately 650 nanometers.
RH - Abbreviation for relative humidity. The relative humidity is expressed in %, and measured with a hygrometer.
S - Abbreviation for sulphur, a nutrient which plants need only in small quantities.
Salts - Nutrients, such as NPK, but also other materials (Ca, Mg,
etc.) which are dissolved in water so
they can be fed to the plant. We call the solution of such materials salts.
Semi-permeable walls/membranes permeable - Play a role in osmotic
processes in plants by which the transport of water
and nutrients takes place, and the plant gets its strength.
Skuff - Sifted tops, from which you get as-pure-as-possible THC.
Stoma - An organ in the leaves of plants. The stomata allow the plant
to breathe. Oxygen and excess water are
released through the stomata.
Substrate - The 'soil'. Thus rockwool substrate means 'soil of rockwool'; the growth medium.
T-44, T-77 - Measures for sieves with which you can sift out THC resin.
THC - tetra-hydro-cannabinol.
Trace-element - Another name for micro-element, nutrients the plant
needs in only minute quantities, such as boron and manganese.
Vegetative- The growth phase of plants.
This lasts phase - only a short while in the cultivation of cannabis;
from one week to ten days maximum.
Zn - Abbreviation for zinc, a nutrient which plants need in small quantities.
PART I: Introduction
Chapter 1: A Short History of Hemp in the Netherlands
This book is not about the enjoyment of smoking or eating cannabis and hash. We can conclude that the home grower knows how to estimate the value of his or her own product, can't we? We'll just leave those stories about the nice feeling for what they are. We spend no time on the effects of cannabis products. Everyone knows what a good 'high' feels like; what you have to do, and what you sometimes have to allow to happen. This first chapter deals with the history of cannabis in the Netherlands. This way, you get a little insight into how the plant has come about in the Netherlands, and what purposes the cultivation of cannabis has served in the last centuries.
1.2. The journey
China is known principally for its tea and opium, the great number of its people, and the hughe amount of Chinese restaurants. also hemp originates from China. The Chinese were already cultivating cannabis 4500 years BC. They were able to spin yarn for clothing, and make fishing nets and rope with it. The first medicinal applications were described two thousand years later. It was used for rheumatism, gout, malaria, and a number of other disorders.
From China, hemp travelled to Arabia, and appeared in the writings of
the Greek philosopher Herodote. He describes ritual use of burning hemp
by the Syrian Skytes.
Hemp grows everywhere. It came to Europe via India and the Roman Empire. In the Middle Ages, hemp's intoxicating effect was described by Boccaccio and Rabelais, among others. Later, it was used by Victor Hugo, Honoré de Balzac, and Alexandre Dumas in the Latin Quarter in Paris.
Scholars do not agree as to whether the Spaniards were the original importers of cannabis to America. It is certainly true that Colombus' ships were outfitted with hemp rope, and sails made from hemp cloth. The plant spread quickly in America, and at the beginning of the seventeenth century, large-scale hemp plantations proceeded in order to supply the needs of the ship- and clothing industries.
1.3. Cannabis in the Netherlands.
It wasn't any different in the Netherlands. It's not exaggerated to suggest that a considerable portion of the wealth of the Golden Age came from the cultivation of hemp. Some 11,000 ships sailed at that time, rigged with rope and sails made of hemp. Hemp was the leading agricultural product in the Netherlands; the stalk was primarily valued. The stalk, only from the male plant, was processed into hemp fiber. The female plants were used for other purposes. These were harvested later, and then threshed. The seed was used as bird feed, or was processed into oil, green soap, and raw material for paint. For the latter application, a thick pulp remained which served as animal food. After the Golden Age, less and less hemp was cultivated in the Netherlands. Competition arose from cheaper Russian hemp, along with other fibrous materials such as coconut and sisal. The steam engine made its entry, so less rope and sails were needed in the shipping industry.
Just as in other countries, the medicinal effects of the plant did not go unnoticed by its growers. Rumours had it that witches used hemp in their witches' salves. The effects of hemp had already been described in "The Herb Book" by Rembert Dodoens in the sixteenth century.
Using cannabis products for pleasure really didn't come about in the Netherlands until after the Second World War. After jazz, and later the hippie influences, cannabis smoking blew over from America. In 1962, Simon Vinkenoog a Dutch liberated poët, wrote: 'In ten years, this will be as common as drinking whiskey or beer, or just as normal as an ordinary cigarette. And it doesn't give you lung cancer'. In the first decades, youbetter smoked imported hash than 'Nederweed'. Still, growing at home was so energetically pursued, that, thirty years later, Dutch weed ranks as the best in the world. There has been improvement, cross breeding, and cloning; fighting the currents, at first. Until the mid-Seventies, growing, possessing, and use of soft drugs was still punishable. Not until after the mid-Seventies tolerated points of sale originated - the coffeeshops.
CO2 intake in the leafs Light, air and water, the bare necessities
And now it seems there's no stoppping it. more and more of people use soft drugs, and more and more people try to hold down the costs of soft drug use by going to work for themselves. Sometimes, purely for their own use, sometimes to earn a few cents, sometimes to get rich.
This book has been written for the growing group of people who want to apply themselves to home cultivation. Now, this is the place to give a few warnings. In the first place, it may be generally presumed that smoking is not considered the best thing for your health. In the second place, even though the Dutch government has become more open-hearted in its tolerance of the growth, possession, and use of cannabis, the substance still stands on List 2 of the law on narcotics.
That doesn't pose a problem anymore, if it's for your own use, but
for large-scale growing, possession, and dealing - it still does.
Grow-gardens, green-houses, and plantations are still searched out and
destroyed, and a considerable fine usually follows. Ultimately, every
home grower has to gain knowledge and experience before there can be
talk of a good yield. So, don't get discouraged too quickly if it
doesn't go perfectly in the beginning
Chapter 2: Physiology of Plants
To achieve good results, a home grower must know about plant physiology. Plant physiology is the part of biology which is concerned with the way plants grow and flower. In this chapter, the priciples of plant physiology are discussed. With the growth and flowering of plants, it involves a select combination of light, air, and water. For light, it's about sunlight for outside growing, a combination of sunlight and artificial light for greenhouses, and just artificial light for inside growing. For air, the amount of carbon dioxide (CO2) is of principal importance. Water performs various functions. Plants need water (H2O) for the growth process, but also to transport other important materials.
2.2. Principles of growth
Plants change CO2 and H2O into glucose under the influence of light.
Glucose is the chemical building block for the structure and sturdiness
of the plant. From glucose, the plant makes cellulose, the material
which gives plants their fibrous structure. (Glucose is, in fact, stored
light energy). The chemical process in which carbon dioxide and water
are converted into glucose is called photosynthesis (from the Greek
'photos' = light, and 'synthesis' = to compose). Chlorophyll, which also
gives plants their green color, is indispensible for this process. If
all the conditions are right, the following chemical reaction occurs:
6CO2 + 12H2O = C6H12O6 (glucose) + 6O2 (oxygen) + 6H2O
We can deduce a number of things from this formula. To get one part
glucose, we need six parts CO2 and 12 parts H2O. It would seem that less
water is necessary. When we look at the chemical formula, six parts
water are also produced next to the 6 parts oxygen, and 1 part glucose.
However, research has shown that in the chemical process, 12 parts water
are needed. The 'excess' water is used in the intermediate steps. The
water does not re-appear until the end of the process. CO2 is a gas in
the atmosphere. There must always be sufficient carbon dioxide
available, otherwise, plant growth will reduce. Everyone knows that
plants need water From CO2 and H2O, not only glucose, but also oxygen is
made under the influence of light, by the plants with the help of
chlorophyll. For plants, Oxygen is a by-product of growth. For people
and most animals, it's the primary condition of life. This is a good
combination. In fact, in their metabolism, animals do the converse of
what plants do. They convert glucose and oxygen into carbon dioxide and
water to be able to move, and to allow the heart and lungs to work, etc.
CO2, a gas which is exhaled by people, can again be used by plants for
photosynthesis. It can be thought of as a cycle. The glucose made by
plants is an energy source for the plant. Some processes, such as the
intake of water, require energy. Next to that, glucose forms the
building material for all kinds of other processes with which the plant
lets all its specific properties show. It would go to far beyond the
pupose of this book to look into all those chemical processes. For the
reader of this book, it's about getting good results growing cannabis at
home A plant cannot grow without light, air (which contains CO2), water,
and various nutrients. The chemical process in which CO2 and H2O are
converted into glucose and oxygen under the influence of light is called
photosynthesis. When we look at this process a little closer, it
actually involves two different chemical reactions. The first is called
photolysis. In photolysis, water is broken down into oxygen (O), and
hydrogen (H). Both light and chlorophyll are necessary for photolysis.
This is called the light response. The second chemical reaction is
called the dark response As the term suggests, no light is necessary for
the dark response. With dark response, carbon dioxide is converted into
glucose, with the help of the hydrogen produced during the light
response. The distinction between the light- and dark reaction is of
interest to the cannabis home grower in order to gain insight into the
manner in which the plants must be illuminated (and sometimes kept in
darkness). The plants grow optimally only when a good balance is found
between the light and dark reactions.
2.3. Osmotic processes
With osmosis, we mean the processes in which water and nutrients are absorbed by plants. Osmosis is based on the principle that the plant's walls permit some materials to pass through, and others not. Cell walls are semi-permeable. An example: when we place a bladder with a sugar solution in a tank of water, the bladder swells. The sugar solution attracts the water. The more sugar in the solution in the bladder, the more water will be absorbed, and the pressure in the bladder will rise, but don't try this at home! Among other things, osmosis provides for the sturdiness in plants' cells. So much water is taken in that the plant cells become saturated, and the stalk and the leaves stand upright. If too little water is in supply, the plant cells give off the water; slowly, but surely. The strength is lost, and the plant wiltsAnother way for a plant to lose its sturdiness is for osmosis to work in the reverse direction. If there is too high a concentration of materials in the water fed to the plant, the plant will not absorb water. It will release water, and become less sturdy. An example is the addition of too high a dosage of fertilizer to plants. With over-fertilization, plants dry out and burn . . . A second important function of osmosis is the 'hitch-hiking' of salts (nutrients) together with the water that, through osmosis, ends up in the plant cells. Nutrients are necessary to allow certain growth processes to take place. The salts also cause various kinds of plants to develop various properties. That brings flowers, fruit, and fragrances to mind. In general, plants need the following materials in a water solution: - nitrogen, phosphorus, and sulphur for the construction of cells; - magnesium to manufacture chlorophyll; - potassium, calcium, and magnesium for osmotic processes; - water for growth, for the transport of nutrients, and for sturdiness; - iron, boron, copper, manganese, and zinc as building materials. Most of the nutrients for plants are sufficiently present in our ordinary tap water. But not all The law of minimums plays a great role in the feeding of plants. Material that is present in too small a quantity is a limiting factor on the plant's health. So-called 'deficiency disease' appears when a plant does not receive one or more nutrients. For example, a shortage of iron causes rather white leaves, while a shortage of nitrogen causes reduced growth and yellowed leaves. 'deficiency disease' involves not only the direct effect (an unhealthy plant doesn't grow well), but also impaired resistance. If needed materials are lacking, the chance for infection by moulds and vermin increases. We will discuss plant diseases more extensively in a later chapter. In order to raise healthy plants, we need further amplification of the materials which, by nature, appear in our water. This involves primarily nitrogen (N), phosphate (P), and potassium (K). A formulated combination of these materials is available in shops, and is called 'NPK solution'. We differentiate the different nutrients in order of importance. We call the most important the primary nutrients; - the NPK combination just mentioned. The secondary nutrients follow; namely magnesium (Mg), and calcium (Ca). Finally, there is a group of micro-nutrients, also called trace elements. Sulphur (S), iron (Fe), manganese (Ma), boron (B), zinc (Zn), and copper (Cu) belong to this group, among others.
2.4. Intake and transport of materials
Water, and the nutrients dissolved in it (salts), is absorbed through the root hairs of the plant. The condition of the soil plays an important role. Hard dirt allows little space for water to reach the root hairs, a looser soil has much more space, while rockwool substrate can guarantee a good water supply. Root hairs are very important. When they don't work well, the plant receives too little water and food. Growth is retarded. Root hairs are very sensitive; they can easily be damaged by exposure to air and light. Moreover, you can ruin them by careless transplanting, or just by exposure. The intake of water and nutrients requires energy from the plant, so oxygen and glucose are necessary. Ultimately, temperature is a limiting factor. Even if you take care to provide sufficient water and nutrients, the growth of the plant will be impeded if the ground temperature is too low. This is one of the reasons why most plants outside grow very slowly during the winter. The transport of water and nutrients insures that these materials end up in the leaves. Two forces are responsible for this: the suction power of the leaves, (they lose moisture by evaporation, causing suc-tion to occur), and so-called root pressure. Root pressure can be observed when we cut off a branch of a tree in the spring. Moisture comes from the 'wound', and we call this the plant's sap. The suction force of the leaves depends on the evaporation of water through the leaves. Stomata are responsible for this evaporation process. The stomata can open and close. Next to the evaporation of water, they provide principally for the intake of carbon dioxide (CO2) from the air. They also issue the oxygen which is produced. In the previous paragraph, we have seen that plants lose their sturdiness if they lose too much water. The stomata dispose of a mechanism to prevent that: they can close. Generally, a stoma will be open if there is light, (thus providing for CO2 intake, and for optimal suction power of the leaves), and closed if it's dark (when no CO2-intake, or evaporation is necessary). If the air is extremely dry (dry, hot, mid-summer days!), the stomata can also close during the day. For stomata to work properly, a clean surroundings is necessary, since a stoma can become blocked with dirt particles. Sufficient potassium (nutrients!) are also needed.
2.5. Factors influencing the growth of plants
We conclude this chapter with a summ-up of the principal concerns
for the optimal growth and flowering of plants. The following factors
are the most important ones: - the correct temperature; - the correct
CO2 content in the air; - the correct light intensity, with the correct
wavelength of the light; -the correct amount of water and nutrients -
the right soil; - (for cannabis growers) the right seeds or
cuttings/clones; - 'green fingers' In the second part of this book, we
discuss which materials you need for growing at home. We take a deeper
look into the different factors which influence growth and flowering.
Summing up this comes down to an optimal control of climate.
PART II: Necessities and Climate Control
Chapter 3: Necessities and Basic Installations
In this chapter, everything necessary for home-growing is discussed. After describing the conditions required for your grow room, we pay some attention to the materials you need to get started. Two things are always important: proper climate control, and complete safety. Growing plants indoors roughly involves three things: light, air, and water. After listing the necessary materials and equipment, we reveal the most important aspects about how you can achieve the best results.
3.2. The grow room
The first requirement for a grow room is that it must enable you to
know how best to control the temperature, air circulation, and humidity.
In any case, for good climate control, it is necessary prevent draught.
For this reasons, a garage or a shed are often less suitable. If you see
possibilities to make a garage or shed free of draught, then, of course,
there is no objection. The grow room must be completely screened off.
Make sure that everything not directly involved with growing is removed.
That way, you prevent the chance for moulds and insects as much as
possible. In fact, the grow room should be just as sterile as the
operating room in a hospital You can only expect optimum climate control
if the room is totally sealed. In practice, that means taping up windows
and don't forget aal the gaps and narrow openings around doors and
windows . In some cases, it is advisable to place a wall as a screen
between the other activities in a room. When growing under artificial
light, it is important that the walls of the grow room absorb as little
light as possible. Experiments have proved that flat-white paint has the
best light-reflecting properties. So, cover the walls of the grow room
with matt white paint. This will maximize the light-yield per lamp. The
space must also be arranged in such way that everything is within reach.
That means you have to have room to walk around the tanks or tables
where you're growing. It also means leaving enough space to take care of
your lamps, and be able to water all the plants. A garden measuring 3x3
meters needs 200 liters of water per week, or more. All that water is
not absorbed by the plants' roots, thus a drainage system is needed. The
floor must be a smooth material; concrete is ideal. With other kinds of
floor surfaces, it is advisable to use (white) vinyl or linoleum. Also
consider an upright brim, so that water cannot leak to lower stories of
the building. Finally, it's handy to have a place to store the tools
you're using. A small cupboard (painted matt white!) in the grow room is
best. There's another reason to work in a well-sealed grow room: your
activities should not be seen. Also, make sure that the bright lights
you'll be using aren't visible from outside . . .
3.3. The shopping list
You don't need a lot of equippement to grow cannabis on a (very)
small scale. A grow tank, soil, nutrients, enough light, and an
agreeable temperature make growing hemp indoors quite possible A good
alternative for growing in soil is to fill planting pots with lava stone
granules, or with rockwool flakes. In order to achieve a smooth growth-
and floweringprocess you must pay a lot of attention to ventilation,
regular watering, proper lighting, etc. Without appliances, you have to
care for the plants every day. Therefore, you have to choose between
growing in soil or in rockwool. Working on rockwool is advantageous
because you don't have to drag bags of soil around Still, some weed
growers swear by soil, because they think the quality of weed isn't as
good if you grow on rockwool. Others see no difference. They would
rather grow on rockwool, because they can achieve a greater yield. There
are, however, many factors which affect the healthy growth and flowering
of cannabis. 'Green fingers' are certainly not the least important We've
made a shopping list for (semi-) professional growing on rockwool
substrate. Cheaper alternatives can be devised for many of the articles.
We'll return to the three aspects light, air, and water later in greater
detail. The materials listed below will cost between 2250, and 3000
guilders for a grow space slightly larger than two square meters:
- 3 armatures for high-pressure gas lamps;
- relay box for the lamps;
- 12 libra trays with water drainage;
- 12 rockwool slabs;
- 36 rockwool blocks 7.5 x 7.5 x 6.5 cm;
- irrigation system with an immersible pump, electric timer clock, water
reser voir, air pump, heating element
- ventilator for the intake and outlet of fresh air and the discharge of
- measuring cups (100 and 500 ml);
- pH meter;
- EC meter;
- thermometer with indications for minimum- and maximum temperatures;
- saltpeter/phosphoric acid.
Unfortunately, you're still not ready, even with the materials listed
above. Optimum climate control is needed for growing indoors. A
ventilation system can (and in some cases, must) be added; varying from
a simple bathroom ventilator to a more expensive carbon dioxide box
ventilator with a humidifying system. You can go for a larger-scale
approach by providing a system to keep the CO2 content optimal, by
installing air-conditioning, or your own water purification regulated by
osmotic filters, or by using a computer to regulate feeding. You can
easily spend more than 20,000 guilders for a complete home-grow system
if you want .
CO2 computer flow-unit
3.4. Grow room layout
First, the lamps are installed. It's important to ensure enough power
capacity. The three lamps together require 1200 watts of power, while
the pump and the ventilator also draw current. The safest manner is to
allow a separate circuit in your tool cabinet. With a 16-ampere circuit,
you have 2800 watts at your disposal. The circuit does provide more
power than that, but you cannot use it all. When the lamps are turned
on, they use more power than the 400 to 600 watts they give off. Too
high a current drain will blow the fuse The lamps must be distributed so
that the entire growing surface will be evenly illuminated.
It's a good idea to build a wooden frame to hang the lamps, and to hold
the libra-trays. Other devices can be fastened to the frame later.
Second, the libra trays are arranged. libra trays are well-suited for
growing indoors, because they provide drainage for water run-off. We can
also use so-called drainsets. These should be assembled first. When
they're assembled, they can be snapped onto the trays. If you don't have
access to a drain, it's wise to build a drainage tank. As an alternative
to libra trays, you can, of course, use ordinary pots. If you don't want
to use drain sets, you can drain water via gutters. The growing trays
are filled with rockwool slabs. Holes are cut into the slabs for the
rockwool blocks. The blocks are fastened to the slabs with pins. The
rockwool blocks are saturated with water and fertilizer. After laying
out the irrigation system, the rockwool slabs are then cut on the
underside in order to allow excess water to drain. We'll set up the
irrigation system. First, make an electrical outlet (earth ground!). The
outlet should be conveniently located, right next to the fertilizer
tank. We'll put the fertilizer tank just next to, or even underneath,
our grow-table(s). The immersible pump is placed in the fertilizer tank
to pump the fertilizer to the plants. The pump is turned on and off by a
timer switch. This way, we make sure the plants get their water and
nutrients on time. A tube is attached to the pump. This tube is
connected to a flexible polyethylene hose. This polyethylene hose is
suspended over the middle of the libra trays. The end of the hose is
sealed with a cap. Punch holes for the sprinklers. The next step is the
installation of an air pump with an aerator. The aerator is placed in
the nutrient tank so algae won't grow so rapidly. The air bubbles
generated by the pump and the aerator take care of that. This way, you
also insure that sufficient oxygen gets in the water, and that the
fertilizer components remains in motion. Next, put a heating element in
the nutrient tank. The element has to maintain the water temperature. To
be able to check the temperature, we place a thermometer in the tank.
Watering can now begin; the nutrient tank may be filled with water and
the proper amount of fertilizer. Pay attention when you mix the
fertilizer. Follow the directions on the package accurately. They
describe the correct amounts of fertilizer to apply.
Ph and Ecmeter
With too little feeding, the law of minimums comes into play; delayed
growth and flowering; unhealthy plants. With over-feeding, the plants
will burn . When you apply various kinds of fertilizer (also called A-
and B-nutrients), make sure the materials don't make contact with each
other. If that happens, then a chemical reaction occurs between the
phosphate in the one, and the calcium in the other. Calcium phosphate
forms, and the fertilizer loses potency To find out whether or not the
fertilizer you're using has the right concentration, we use an EC meter
(see the chapter about water). With too low an EC measurement, you
should mix in more fertilizer. With too high a reading, you should
dilute the solution with more water. In addition, the acidity of the
water - the pH value - is important. We measure this with a pH meter
(see the chapter on water). When the pH value is too high, we can lower
it with saltpetre/phosphoric acid. When the pH value is too low, we can
raise it with a solution of calcium carbonate. You must be very careful
with concentrated saltpetre/phosphoric acid. It will burn holes in your
clothes, and it will seriously burn your skin, too The irrigation system
is now ready to be tested. Always make sure the water pump is never
turned on in the absence of water. This can burn up the pump's motor.
Place a sprinkler in one of the measuring cups and determine how much
time it takes to pump approximately 50 cc of water and nutrient into the
measuring cup. Program this time into your timer. It's intended that
each plant gets around 300 cc water and fertilizer, divided over at
least 6 feeding times. If you have a timer which can be switched on and
off more often, then you can spread the 300 cc over more feeding times.
As an example, we'll consider 6 times. The first 50 cc feeding is given
at the moment the lights are turned on, and the last, two hours before
the lights are turned off. The other four feedings are neatly divided,
via the timer clock, among the periods in between. Plants take in water
and nutrients only under the influence of light. This is the reason for
giving water and nutrients when the light is on. The last feeding is
given approximately two hours before turning the lights off; in order to
give the plants the chance to absorb the water before the dark period.
The quantities we refer to in this book are average values. The starting
point of every grower must ultimately be raising healthy plants. So you
also have to have green fingers as you do the watering and feeding
Next month Chapter 4.
Chapter 4: Light
watertank with the needed accesories
Plant growth involves the conversion of light energy into plant-building materials (photosynthesis, see chapter 2). Two factors are important for optimal growth. In the first place, the light intensity. Light intensity is expressed in 'lumens'. At least 50,000 lumens are needed for growing indoors. It's not sufficient to add up the number of lumens listed by the manufacturer for each lamp. The total number of lumens given off is depends strongly upon good reflection, and proper connecting fixtures and starter ballasts for the lamps. The quality of the reflector used, and the connecting fixtures and ballasts determine the light yield for the greatest extent. For those reasons, self-built sets and home-designed illumination often deliver a lot less light yield than lamps being used in professional horticulture. We can improve the light yield in our grow room by applying reflective material. We haven't painted the walls of the room matt white, and used reflector caps for the lamps for nothing! The second important factor is the wavelength of the light. For the production of chlorophyll, and an optimum photosynthetic reaction, light from the blue spectrum (445 nanometers), and light from the red spectrum (650 nanometers) is necessary. Blue light ensures optimal phototropism. Phototropism is the phenomenon which causes plants to grow towards the light, and to spread their leaves in such a way to receive the most light.
4.2. Choices for lamps
In this book, we prefer high-pressure sodium lamps, and mercury-iodide
lamps for illumination. Ordinary light bulbs are not suited for
cannabis-growing due to their considerably short life span, and
principally due to their low light yield. Halogen lamps are not
advisable for the same reasons. Fluorescent lamps are not appropriate
for home growing. They do serve well, however, to stimulate seedlings
and cuttings to set root. For actual growing, we stick to gas discharge
lamps in the form of high-pressure- sodium, and mercury-iodide lamps.
There are lamps being sold which emit both the wavelengths needed (blue
and red) but we prefer installing seperate lamps in a 1:3 proportion (1
lamp for blue light with 3 for red light). The combination lamps give
off a lower amount of lumens, since they have to emit different
wavelengths. This counts for growing: the more lumens, the greater the
yield. This doesn't mean we can install an unlimited number of lamps.
Other factors must be considered. Using many lamps means a higher
temperature (the heat must be discharged of), a greater need for fresh
air (containing CO2), and a greater need for water and feeding. Always
remember the law of minimums Depending on the size of the garden, we use
400 Watt lamps or 600 Watt lamps. This choice is made in such a way that
all the plants in the garden area can be illuminated as evenly as
possible. By using 400 W lamps, you can put up one-and-a-half times as
many lamps for the same electricity use as when using 600 watt
lamps.Also 1000 watt lamps are being sold but proper reflectors for
these types of lamps are not available. The result is a
disproportionately large loss of yield. Moreover, 1000 Watt lamps give
off more heat. Therefor they must be hung high above the plants, and
this means more loss of light yield plays in the question. 1000 Watt
lamps, with respect to 400 and 600 Watt lamps, mostly cause pain in your
wallet, because the electricity bill gets higher.
In practice, it is possible to reach a light yield of 70-90% of the
lumens which are emitted. For that, (it can't be stressed enough), good
reflection is necessary. Below is a chart with data for several
reflective materials: Reflectivity in % - Reflective plastic sheet 90-95
- matt white paint 85-90 - semi-matt white paint 75-80 - matt yellow
paint 70-80 - Aluminium foil 70-75 - Black paint less than 10 Using
proper reflective material, proper connecting fixtures ballast
equipment, proper reflector caps with the lamps, and a distance from the
lamps to the plants of 40 to 60 centimeters, 400 Watt lamps deliver, on
average, between 35,000 and 47,500 lumens, and 600 Watt lamps between
60,000 and 80,000 lumens (at a distance of 50-70 centimeters). The
distance between the plants and the lamps differs because 600 W lamps
give off more heat. Ifthe plants are to close to the lamps, they will
dry out and burn 600 Watt lamps are preferred, because you get the
highest light yield for the lowest electricity cost. Though they do
require more careful climate control The life span of a high-pressure
gas lamp is approximately 2 years when it's used 18 hours a day. The
lamps are, however, subject to decay, which lessens the light yield.
In practice, it appears that high-pressure gas lamps give optimal
results for 4 to 5 harvests. After those, it's advisable to replace
them. It seems that the installation of one 600 Watt sodium lamp per
square meter is enough to achieve the best results. Principally one can
say 'the more light, the better', but with more illumination, the
control of other factors (namely, temperature control) becomes a
problem. Indoor growers work with their light source close to the
plants. Considering the light yield of the sun, (hundreds of thousands
of lumens, but a little further away), fewer lumens are needed for
growing indoors. A simple formula shows that you can also use three 400
W lamps for two square meters. The sodium lamps provide light from the
red spectrum. This light is used principally during growth. A
mercury-iodide lamp fills in the blue spectrum. For reflection, growers
use wide-angle reflectors with sodium lamps, and super-wide-angle
reflectors with mercury-iodide lamps. Super-wide-angle reflectors spread
the light over a greater surface area. We use the proportions of 3 red
lights to 1 blue. So, the light from the blue lamp must be spread over a
larger surface area.
4.3. Using high-pressure gas lamps
High-pressure gas lamps may only be used in the fitting meant for
that particular lamp type. High-pressure gas lamps all have their own
start-up conditions, voltages, characteristics, and shapes. Using lamps
with improper sockets can cause electrical shorts! Therefore, it's
recommended that you buy all the parts of a pressurized gas lamp from
the same dis- tributor. The sockets, ballasts, and connectors must
always be protected from humidity; otherwise, electrical shorts occur.
As stated earlier, high-pressure gas lamps have a long life span. You
must be careful when replacing these lamps. They are, as the name
implies, under pressure, and they explode when you destroy them. When
you do that yourself, you must always wear gloves and safety glasses. In
addition, you have to protect yourself against the poisonous materials
found in these kinds of lamps. The heat given off by high-pressure gas
lamps, and their accompanying starter ballasts, must be completely
ventilated. This means that the lamps shouldn't hang too close to the
plants (hence drying and burning occurs), but also not too close to
(flammable) ceilings and walls. Place a piece of non-flammable material
(not asbestos!) between the lamp and ceiling or wall. Furthermore t's
necessary to discharge of excess heat by using a ventilator. Finally,
it's important to keep high-pressure gas lamps clean. Dirty lamps
provide much less light yield than clean ones. The lamps should be
polished now and then with some glass- cleaning agent. That should be
done only when the lamps are turned off, and well-cooled.
the use of gloves to protect the lightbulb cloning accessories
Be especially careful with water. Lamps which are still hot, or even
warm, can explode when touched, and that's not funny Also, take care
never to touch these types of lamps with your fingers. Just like halogen
lamps, bodily acids can burn through, causing the lamp to fly to pieces.
4.4. Proper lighting for cannabis
The advantage of growing cannabis indoors is the fact that you can
give the plants the feeling that it's their flowering season all year
round. You're not dependent on the weather or the season. We distinguish
two separate phases in plant cultivation: the growth- or vegetative
phase, and the flowering- or generative phase. We've already made sure
the lamps are installed in such a way that all the plants can be
optimally illuminated. A light period of 18 hours and a dark period of 6
hours is ideal for the vegetative phase. We're assuming that you already
have cuttings with roots. With proper care, a healthy cannabis plant can
grow up to 5 centimeters per day. It's very easy to cause the plant to
flower. We only have to give the plants the idea that the days are
getting shorter ('autumn'; for cannabis, the sign to flower). We do that
by making the light and the dark periods the same length; - 12 hours. In
principle, cannabis is an annual plant. The entire life cycle, from seed
to death, takes place in one year in nature. When growing cannabis under
artificial light, it is possible to force flowering earlier than in
nature. After 4 or 5 days vegetative phase, flowering can be 'provoked'.
We do that the moment the clones have visibly started to grow. Two or
three weeks after the light period is reduced to 12 hours, the plants
begin to flower. It's very important not to interrupt the dark period.
If the plants receive light during the 12-hour dark period, they 'get
confused'; they want to continue growing, and the blooming phase is
postponed. The generative phase lasts 60 days or longer, depending on
the variety you're growing. When working with cuttings, it's possible to
harvest four to five times a year.
the cutting or clipping of a clone and the motherplant and its clone on
a rockwool plug
Chapter 5: Light
Almost all living beings are dependent on light of satisfactory quality.
For humans, that means that sufficient oxygen must be present in the
air, and that the air is not too polluted. For plants, and thus also for
cannabis, it means good air quality, enough carbon dioxide (CO2), and
not to much pollution. Relative humidity (RH), and temperature also play
a large role in the growth of plants.
5.2. Influencing air quality
The amount of CO2 in the open air is appoximately 0.03 to 0,04%. The
amount of carbon dioxide is also expressed in parts per million; ppm.
0.03% is equal to 300 ppm. There are differences in the CO2 needs among
plants. By raising the CO2 content, growth can be accelerated. The law
of diminished returns still holds true, however. Raising the CO2 level
has limits, but at approximately 1400 ppm (0.14%), good results (a
faster growth) are generally achieved. Above 1400 ppm, the effect of a
higher percentage of CO2 decreases. A high concentration of CO2 is
poisonous even for plants. A CO2 concentration of 1800 ppm or more is
deadly for most plants. A simple method for guaranteeing the supply of
carbon dioxide is to ventilate the room. Sufficient ventilation must be
provided, so the plants keep getting enough fresh CO2. A second and just
as important reason for ventilation, is to dispose of excess heat. If
the temperature gets too high, (see Section 5.4), growth is stunted.
This counts not only for the temperature in the grow room, but also for
the temperature in the plant itself. When the plant's temperature is too
high (humans get a fever), there is less sap flow, causing growth
distubances. There is no standard solution for refreshing the air. The
need for fresh air is, for a large part, dependent on the size of the
grow room in cubic meters. In principal, the total air content of the
room must be exchanged every 2-3 minutes. Using for example a grow room
3 meters long, 2 meters wide, and 2 meters high (12m3), this means that
the ventilator capacity must amount to 30 x 12 = 360 m3 per hour. A
standard bathroom ventilator can only handle up to 100 m3 per hour Many
growers ventilate their rooms with table fans. The point is the control
of the temperature as well as the circulation of the air with sufficient
carbon dioxide. Table fans are primarily intended to keep people
comfortable on a hot summer day. They are much less suited to run
continually for heat removal, and for CO2-content maintenance. Table
fans have a tendency to melt with intensive use. You can imagine the
consequences: not only the danger of fire, but also massive plant death
. . . There are, of course, plenty of fans on the market which will take
care of proper ventilation. These have been specifically designed to be
able to run continually. The CO2 content in the grow room can also be
heightened by adding CO2 from a tank. If the system is set with a timer
clock, the desired amount of CO2 can be regularly released. Work with
care, because you don't know how much CO2 is in the room at any given
moment. An overdose can easily occur To prevent this, it's sensible to
ventilate the area well before each CO2 'injection'. The most
professional option is to use a CO2 controller. This apparatus
continually measures the CO2 content in the room. When the programmed
minimum value is reached, CO2 is automatically added. If the programmed
maximum is exceeded, the controller turns on the ventilating system. If
CO2 is added to the room via a tank, or a controller, cultivation can
take place at a higher temperature. (More about this aspect in Section
5.4.) Ultimately, attention must be given to the relationship between
ventilation, and the relative air humidity. The humidity of the air is
dependent, among other things, on the amount of air moved through the
room. Changing the air draws more moisture out of the plants, because
the stomata release more moisture. If the relative humidity of the air
drops too low, the stomata close, delaying the growth process.
5.3. Relative humidity (RH)
The relative humidity of the air influences the functioning of the
stomata, among other things. Cannabis flourishes the best with an RH of
60-70%. At higher RH percentages, the stomata have problems getting rid
of excess water. At a lower RH, the stoma keep releasing water until the
plant dries out. At that moment, the stomata close. Then, the intake of
CO2 stagnates, and plant growth is impaired. The relative air humidity
is also influenced by the temperature in the growing space. In the chart
below, you can see the number of grams of water which can be absorbed in
a 25 m3 room (for example: 3 x 3 meters, and 2.5 meters high).
Absorption in grams of water (degrees C) 0 degrees 120 10 degrees 240 20
degrees 460 25 degrees 630 30 degrees 840 35 degrees 1120 40 degrees
1460 It may be concluded from this chart, that with every rise of 10
degrees in temperature, the air humidity doubles. Ventilation influences
the relative humidity. Ventilating a space makes the RH fall. In some
cases it's necessary to install a humidifier in the grow room. The best
results can be achieved by using a discharge fan with a variable speed
control. This way, you can easily regulate the quantity of air to be
removed. When the plants are in the dark, the temperature is lower (the
lamps don't give off any heat). So, you would expect the relative
humidity to fall (less moisture can be absorbed by the air). But this is
not the case; RH increases in the dark. The plants breathe out water in
darkness. Therefore, sufficient ventilation must be provided. Too high a
humidity level provides considerable risks for the health of the plants.
Generally, pests and diseases (see Chapter 8) have a better chance with
a high humidity level. Too low an RH is also risky; the plants can
easily dry out. Prevention is better than cure . . . Finally, it should
be stated that young seedlings and clones generally perform better at a
humidity level of 65-70%. Their root systems are not yet developed well
enough to take in water fast enough. A higher humidity insures that the
young plants will be protected from drying out.
The high-pressure gas lamps we use for cultivation cause a considerable
amount of heat in our closed-off grow space. This heat can be damaging
to the plants. In the first place, we have to make sure the plants are
not too close to the lamps. A distance of approximately 40 centimeters
(for 400 Watt lamps), or 50 centimeters (for 600 Watt lamps) is good.
The lamps also warm the air in the room. This heat must be discharged
via the ventilation system. Cannabis seems to grow best at a temperature
of 25 to 26 degrees Celsius. This temperature must not be allowed to
rise any higher in grow rooms where no CO2 enrichment takes place. When
working with bottled CO2, or even a CO2 controller, the temperature can
be a little higher; 27 to 29 degrees. When working at higher
temperatures, the RH must be closely monitored. Every 10 degree rise in
temperature means that the absorption capacity of the air nearly doubles
(see Section 5.3). In the dark period, the temperature may drop a
little, but not too much. If the temperature is too low during the dark
period, moulds have a better chance A temperature of approximately 20
degrees Celsius is ideal for darkness. In order to maintain an optimal
temperature, you need a discharge ventilator. The discharge ventilator
has a double function: refreshing the air, and drawing off the heat. As
described earlier, the capacity has to be great enough to replenish the
air content of the grow room at least thirty times every hour.
Accordingly, when working at higher temperatures (by adding CO2), the
plant needs more water and more feeding. Remember the law of minimums.
We can raise the CO2 supply, but if we don't give extra water and extra
fertilizer, plant growth adapts itself to the aspect of poor care.
Chapter 6: Water
With the short description of plant physiology, we already looked into
the function of water in plants. Water has three functions: it is a
building material (together with CO2 and light energy, glucose is
produced), it makes the plant sturdy (the plant cells fill themselves
with water, giving the plant a firm structure), and it transports
nutrients throughout the plant. Water is indispensable for the existence
of plants. Remember that the law of minimums plays a crucial role here
also: too little water, but sufficient light, CO2, and nutrients,
produces unfit plants. Too much water, with respect to the other
criteria, produces just as poor results. Therefore it's important to
find an optimal balance, so the plants will flourish.
6.2. Water quality
It probably goes without saying, but the water you use must be as clean
as possible. For plants, however, 'clean' is a relative concept.
Nutrients such as nitrogen, phosphate, potassium, etc. are always
dissolved in water used for plant food. In any case, the concentrations
the plants need of these materials make the water undrinkable for
humans. In contrast to 100% distilled water, 'pollutants' are found in
ordinary tap water. You can request a chart with data about the quality
from the company that produces your drinking water. The hardness in
degrees - the GH (German Hardness) - is also given. This is a measure
for the amount of calcium in the water. Below, you have an example of
this kind of water chart. Some of the 'pollutants' aren't 'pollutants'
to plants, but actually fertilizing materials. To determine the water
quality (and the plant foods you add), you need two types of meters. The
first is an EC meter. 'EC' is the abbreviation for 'Electrical
Conductivity'. Pure water, also called demineralized water, does not
conduct electricity. When we add fertilizer to the water, or the water
is 'polluted' in some other way, the water will indeed conduct
electricity. Fortunately, home growers can make use of this property of
water. With the EC meter, we can determine whether or not the
concentration of nutrients in the water will provide for optimum plant
growth. A high EC value means a high concentration of fertilizing
materials, and a low EC value, a low concentration. Too high a
concentration shows that you're over-fertilizing. As a result, your
plants will dry out and burn. (By osmotic processes, water is drawn out
of the plant; the leaves curl upwards or downwards.) The fertilizer
concentration must be lowered by further diluting with water. Too low an
EC value means a shortage of fertilizer. This decreases the growth on
rockwool substrate. The EC value is given in millisiemens. 1.8
millisiemens is the optimal value for growing cannabis. The second type
of meter is the pH meter. With a pH meter, you can determine the acidity
of water. Most of us have measured the acidity of a solution at one time
or another in high school. We did it with a litmus test. But the litmus
test is not suitable for measuring acidity when growing hemp at home.
The accuracy of this test leaves something to be desired. Actually, we
can only estimate the pH value, to the accuracy of one pH point. We need
greater accuracy for cultivating cannabis. The average pH meter used by
aquarium owners is relatively cheap, and meets the requirements well.
Generally, they're up to 0.02 pH points accurate. The ability to absorb
nutrients depends on the acidity of the water. If the pH is too high or
too low, the plants can't absorb some nutrients properly. Then
deficiency disease occurs . The pH scale goes from 1 to 14. A solution
with a pH between 1 and 7 is called 'acid', a pH of 7 is called neutral,
and between 7 and 14, 'basic'. The lower the pH, the more acidic the
solution (in our case: water). On the next page, you have a chart
showing which nutrients plants can absorb best at each pH. You can read
from the chart that cannabis plants like it if they receive water which
is slightly acidic. The home grower must make sure that the pH of the
water being used is approximately 5.8. The EC meter, as well as the pH
meter, must be adjusted now and then. Special calibrating fluids are
available for this operation. The temperature is also an important
factor when calibrating an EC meter. The correct temperature is listed
on the package of calibrating fluid. A pH meter has two set screws, and
it must be adjusted to two values. The probe of the pH meter is first
dipped into a calibrating fluid with a pH value of 7.0. Then, this value
is set using one of the set screws. After that, the probe must be
cleaned well; otherwise, deviations will occur with the second
calibration. Next, the probe is dipped in a calibrating fluid with a pH
value of 4.0, and this value is set using the other set screw. It's
important that the pH meter probe is kept moist. Depending on the type
of pH meter, it may be stored in ordinary tap water, or in a special
fluid supplied by the manufacturer. In the story about the EC meter,
we've already indicated that the temperature of the nutrient solution
influences plant growth. Cannabis grows best with a water temperature of
25 degrees Celsius. Below this temperature, the roots of the plant have
more trouble taking up water and nutrients. Too high a temperature is
not good either. That will kill the plants Tap water must be warmed up
to 25 degrees C. Use a water thermometer to keep an eye on the water
temperature. Warming the water is easy with the installation of a
heating element in the nutrient tank. This equipment also comes from the
aquarium world. Quality heating elements with thermostats are available
for aquariums. For a 100 liter nutrient tank, you need a 100 Watt
heating element; with a 200 liter tank, we recommend a 250 Watt element.
Make sure the heating element is always kept under water; otherwise it
will be destroyed. This means that you must never pump all the water out
of the nutrient tank to the plants. When you want to take the heating
element out of the water, always disconnect it first. Then, let it cool
off for at least 15 minutes. Only then can you carefully take it out of
the water. Any other way, you run the risk the element will crack. To
prevent algae growth in the nutrient tank, it's important to add air to
the water. We do that by means of an aquarium pump with an aerator
attached. The aerator is connected to the pump, and placed at the bottom
of the nutrient tank. The water in the tank becomes rich in oxygen by
aeration, and is also kept in motion. This way, algae have much less
chance to proliferate.
6.3. The irrigation system
We do everything we can to promote plant growth. We provide optimal
lighting and sufficient CO2. As a third component, regular irrigation is
an essential link. This way the plants receive their water and nutrients
in time. The easiest way is to water by hand several times a day. But,
in the first place, that involves carrying a lot of watering cans
around, in which you've dissolved the correct amount of fertilizer every
time. In the second place, watering by hand requires enormous
discipline. Giving water regularly on time will quickly 'water' YOU down
You can't skip a few days here and there, and leave your plants to
themselves. Finding a babysitter for cannabis plants is often more
difficult than finding a babysitter for your kids . . . So, we prefer to
give water regularly with an irrigation system controlled by a timer
clock. This way, we can rest assured the plants get their wet and dry
periods on time. In Chapter 3, we've given a lot of attention to the
installation of an irrigation system. Now, we'll go a little deeper. In
its simplest form, an irrigation system consists of an immersible pump,
controlled by a timer clock, which has hoses with sprinklers attached to
it. The sump pump is placed in a nutrient tank with a capacity large
enough to make refilling necessary only two times per week. We're
talking about a tank with a contents of at least 25 liters per square
meter of garden space. 5 to 7 liters of water with nutrients are used
every day for each square meter. So, refilling the tank every 3 or 4
days is enough. Remember, there must always be enough water in the tank
to cover the heating element and the pump. Both instruments will be
ruined if they are left without water Preferably, the nutrient tank
should sit on the floor. There are two important reasons for this. In
the first place, it saves space. The tank can also be underneath the
tables. In the second place, it prevents the natural working regarding
water levels between communicating vessels. If the nutrient tank is
placed too high, the water will flow through the hose without the aid of
a pump. This goes on until the water level in the tank reaches the same
level as the lowest point of the connected irrigation hose. Solutions
can be devised for the problem of 'communicating' vessels; - coupling an
electric faucet between the nutrient tank and the irrigation hose, for
example. This solution is unnecessarily expensive. The problem of
communicating vessels can be prevented by placing a sprinkler outlet on
the top of the hose. The sump pump must be powerful enough to send water
to all the sprinklers that will be installed. For a garden 2 to 10 m2 in
size an immersible pump with performance capability of 7 meters is
enough, if used with a 1-inch irrigation hose. Also, the pressure of the
pump should not be too high, otherwise the sprinklers (also called
capillaries) won't drip, but spray Most sprinklers function at a
pressure from 0.5 bar on up. To the immersible pump, we connect an
irrigation hose (polyethylene or PE- hose). The irrigation hose goes
through the middle of the grow trays. Then we make holes in the
polyethylene hose and insert the sprinklers. We install one sprinkler
for every plant. We have to prevent dirt and other materials from
clogging up the narrow openings of the sprinklers. We take two measures:
first, we keep a lid on the nutrienttank so nothing undesirable falls in
the water. Second, we place a filter between the pump and the irrigation
hose. In an ideal situation, plants should get water and nutrients
spread evenly throughout the day. We can arrange for this by connecting
a timer clock to the irrigation system. A suitable timer clock must also
have a minute setting, and must be able to switch on and off at least 6
times a day. Modern timer clocks are digital. These clocks have a memory
to store the desired times. If the electricity goes off, batteries
usually supply current to preserve the memory. The disadvantage is that
batteries run down. If the battery is dead, and the electricity goes
off, the memory is erased. The steady watering stops, and the garden is
damaged. The recommended choice is a timer clock with a good car battery
for backup. Now, our irrigation system ensures that the plants get the
correct amount of water and fertilizer on time. The sprinklers evenly
distribute the nutrient solution. We prefer growing in 'libra trays'; -
so-called 'growing trays' which have been especially designed for
growing on rockwool slabs. There are other methods, of course. You can
also lay rockwool slabs on corrugated roofing sheets, for example. This
does give problems with drainage water . It's more hygienic, and more
practical to work with growing trays. They're not expensive, and it's
simple to connect a drainage system to them. Easier still is snapping
drainage spouts onto the growing trays. Then the water can be drained
into a gutter. We divide the irrigation of the plants into 6 periods
during the 18-hour light cycle. The first feeding takes place when the
lights are switched on. A feeding session follows every 3 hours, until 3
hours before the lights go off again (the plants can take in nutrients
only during the light period!). In the beginning, we don't let the
irrigations periods last more than one minute, because otherwise,
problems with root development can occur. We stick to short feeding
periods. Throughout the entire vegetative phase. During the generative
phase (12-hour light cycle), we also divide the 6 feeding sessions so
the plants will get water every two hours. Since the plants have grown a
little by then, and they need more water, we let the irrigation periods
last for two minutes. When irrigating the plants, you must make sure the
nutrient solutions soaks through thoroughly. Thorough watering means
that about one-third of the water applied drains off. Thorough watering
is important to prevent the accumulation of the nutrient salts in the
rockwool slabs. If watering is not sufficiently thorough, it's sensible
to raise the number of irrigation sessions. Finally, another word about
safety. Everyone knows that water and electricity are equally related as
water and fire. The sump pump, as well as the thermostatic heating
element, work with use electric currency and under water. Use only
equipment of wich you are sure it is well-insulated. Moreover, it's
sensible to disconnect the plugs before you put your hands in the
nutrient tank. This can save you from a possibly shocking experience
PART III: Growing Cannabis
Chapter 7: Clones and Cuttings
In the previous chapter, we've told you what equippment you need to grow
hemp. Furthermore you've been initiated into the secrets of good climate
control to reach an optimal result. Up until now, we haven't said a word
about the living material you can use to 'rise high'(!) . . . In this
chapter, we'll look at the actual cultivation. We'll leave sprouting
cannabis from seed for what it is. We'll talk about starting with
clones. It's not completely clear why the word 'clones' has been adopted
by the weed grower; we're talking, in fact, about 'cuttings'.
7.2. Cloning hemp
Cloning hemp is a cheap, quick way to get plants. The average gardener
has taken cuttings from his/her house plants at one time or another.
It's not much different with hemp. We only have to make sure the
carefully removed cuttings from the mother plant are brought to root. A
healthy mother plant can pass on her THC-producing properties from
generation to generation by means of cuttings. Each cutting has the same
properties as the mother plant. A cutting can be taken from a cutting.
And from that cutting, yet another. There are growers who have raised 20
generations from a mother plant this way, without diminishing the
growing power of the plants. The yield from the 20th generation is just
as good as the yield from the first one! By then, the original mother
plant is long past use. Taking cuttings causes trauma to a plant. The
plant reacts by taking on a deviant form, and by starting male branches.
A third problem is regressive mutation. The mother plant has been
developed by cross breeding. With regressive mutation, the carefully
bred properties (to a degree) are lost. The quality of the plant (and,
of course, the quality of the harvest!) decreases. For this reason, we
replace the original plant with one of her fresh, healthy daughters
after 12 weeks at maximum. The ease with which hemp can be cloned makes
planting cannabis seed less attractive. In the first place, sowing seed
takes a lot more time than growing from clones. An advantage not to be
underestimated is the fact that you can harvest much more often if you
raise clones rather than grow from seed. On top of that, you get males
as well as female plants from seed. The chance that a seed produces a
male plant is just as great as the chance a female will appear: 50% . .
. To make hemp cuttings/clones we need: - a high-quality mother plant; -
sharp scissors, or a sharp knife; - any commercial hormone mixture to
promote root growth; - something to start the cuttings in (a cutting
tray with rockwool plugs, a small grow-tank with washed, rough sand,
fine vermiculite, a soil-free mixture, or potting soil); - phosphoric
acid - a 'cool white 33' fluorescent tubelight with the proper armature;
- ventilation; - clean working methods, and clean sur roundings; -
'green fingers' In contrast to raising cannabis plants, for which we use
400 Watt or 600 Watt high-pressure gas lamps, clones develop their roots
best under fluorescent light. Fluorescent tubes emit light primarily in
the blue spectrum. Controlling the temperature when using fluorescent
lights is also less complicated, because fluorescent tubes give off
little heat. The fluorescent tube armature is mounted approximately 25
cm above the tops of the clones. We're going to illuminate the cuttings
18 or 24 hours per day. We keep the light on 24 hours a day during the
cold months. The illumination times suggested here are a guide. What it
actually involves is allowing the climatological conditions to vary as
little as possible. You get the best results with an even climate. It
requires some experience to create the optimum conditions . . . The hemp
cuttings form their roots best at a temperature of 25 to 26 degrees
Celsius, and a relative air humidity of 70-75%. Just as is the case with
actual growing, climate control is very important for cuttings. Moulds
and pests insects must never get a chance. Above all, mould spores can
cause problems if the climatic conditions aren't optimal. In principle,
every part of a hemp plant is suitable to use as a cutting. But a single
leaf with a few roots is of no use of course In any case, a good cutting
has a growth-point. The size of the cutting doesn't matter so much; a 2
cm cutting can grow to be a top-quality plant, just like a 10 cm
cutting. Before you put the cutting in the growth medium, you have to
make preparations. We're talking about raising cuttings in rockwool
substrate. First, the growing tray should be soaked in a nutrient
solution. The pH value must be 5.8, the EC value 0.8 to 1.0. To reach a
pH value of 5.8, you best use phosphoric acid. The advantage of
phosphoric acid is that it helps the cuttings develop roots. We fill the
tray for the cuttings with the nutrient solution and drain it off again.
We do this several hours before taking cuttings from the mother plant.
The cuttings are clipped, or cut with a sharp knife or scissors. Take
care not to leave the ends frayed. A clean cutting loses less sap than a
cutting with a frayed end. Moreover, there's the risk that ravelled
parts of the plant will rot. Directly after clipping or cutting, we dip
the clone first in water, and then in rooting hormones. Then we stick
the cutting into the rockwool plug. The growing tray for the cuttings
must then be saturated for 3 or 4 days with nutrient solution. Good
hygiene is very important when getting cannabis cuttings to root. Work
as clean as possible. Always clean your scissors, knife and growing
trays with a medical disinfectant (i.e. Dettol) after you've used them.
Check the clones daily for possible rotting parts. Rotting leaves or
stems must always be removed, so that moulds won't get a chance. It's
also important not to put the clone tray in a bed of water. That makes
rooting more troublesome, and the roots will be of less quality. Also, a
too wet clone tray causes root rots such as pythium afungus on the
roots. Just like all plants, hemp cuttings also need fresh air
containing CO2. We have to ventilate the clone room, too. Sometimes,
ventilation is necessary to keep the temperature stable. When using a
ventilator, you must try to create an optimal climate without exposing
the plants to gale force 9. The cuttings can dry out as a consequence of
too much air movement. When you have all the climatic conditions under
control, you can start waiting for roots to develop. It takes about 10
days before you see the first results with healthy plants. After a
fortnight, healthy cuttings will have enough roots to be transplanted.
In principal, approximately 80% of the cuttings will root, if you
control the climate well. Allow the cuttings which have no roots after a
fortnight one more week. These cuttings can produce a plant of lesser
quality. If no roots have grown after 3 weeks, you can throw those
cuttings away. Don't count on all the cuttings taking root; plant about
20% more than you ultimately intend to keep. Planting rooted clones is a
tedious job. The root systems of the young plants are very tender, and
can easily be damaged. The extremely small root hairs are very important
for a healthy plant. Many splendid cuttings have been ruined by rough
transplanting The roots of plants don't like light (they grow in the
dark), and air (they dry out quickly). The young plants will now go to
the spot where they will spend the rest of their lives. For plants,
transplanting more than once is just as traumatic as making people move
house twice a month . . . Now, the plants must become accustomed to
their new surroundings. They must get sufficient water, but not yet the
full amount of light. After a few days, the real irrigation schedule can
begin, and the plants go under the full light of the high-pressure gas
lamps. The vegetative, or growth phase begins . . .
7.3. The vegetative phase
In this phase, the plants are illuminated 18 hours per day, and kept in
darkness 6 hours per day. If all aspects are in order, (sufficient
light, proper ventilation, good temperature, enough water and nutrients,
in short: complete climate control), the plants will grow quickly; up to
5 cm per day. The duration of the vegetative stage is strongly dependent
on the control of climate. The better the climatic conditions, the
earlier the cutting takes root. The vegetative phase lasts from 3 to 10
days at maximum. We'll discuss growing 15 plants per square meter. If we
want to use the surface area to the maximum, then we must prune the
plants; - break off the uppermost part. pruning is possible only with
plants that have rooted and begun to grow. If this is not the case,
breaking or clipping the tops off should be postponed for a couple of
days. By pruning the plants, we ensure that they not only grow tall, but
wide, as well. After cutting off the tops, we leave the plant in the
vegetative stage (18-hour cycle) for a few more days. When the
off-shoots have grown 3-4 cm, we start the generative phase. If all goes
well, three or four large tops will then form on each plant. Then we're
ready to get around 50 tops per square meter. To get a wider plant, you
can now break off the top-most part of the plant. Further pruning is not
necessary. Pruning makes the plant grow fuller. That's not to say you
get a bigger plant, because you've also taken something away . Since the
vegetative phase lasts only a short time, the plant must quickly make up
for the damage. After pruning the top, two new branches will appear from
the budding sight just under the spot where the top was. Be very careful
with pruning; it's a more painful experience for a plant than trimming
your own nails After pruning, it's not unlikely for growth to be delayed
for a few days. It needs no further explanation that a clean,
razor-sharp knife or garden scissors should be used. Actually, we can
only think of one good reason for pruning. When branches don't grow
well, or are sickly or too thin, in short; unhealthy, you can, of
course, carefully remove them. With pruning, it always involves the
removal of the whole branch. Take care to touch the leaves as little as
possible. That can easily disturb the workings of the stomata in the
leaves. Some people swear by removing leaves in order to allow more
light to reach other leaves. This is necessary; moreover, part of the
growth capacity is lost. It's also unnecessary to remove dying leaves.
You only have to clear these away after they've fallen off the plant.
Picking them off earlier might again cause damage to the plant . . .
7.4. The generative phase
After one weekat maximum, we will shorten the illumination time, and
adapt the irrigation schedule accordingly. We keep giving water 6 times
per light cycle. Give water and fertilizer during the period that the
light is on, and not during the dark period. In the flowering, or
generative phase, the plants are in the light for 12 hours, and in
darkness for 12 hours. We imitate a shortening of the day in autumn; a
sign for the plant to start flowering and forming seeds during its last
phase of life. In the generative phase, the plant's emphasis is less on
growth. Less chlorophyll is produced and in the flowering phase, we
often see fewer fingers forming on the cannabis leaf. The plant needs
less blue light during the flowering phase (that was important for
chlorophyll production in the leaves), and it needs more red light. The
autumn sun produces more red light, because the autumn sun is lower in
the sky.That doesn't mean that you must now use only the sodium lamps.
With only red light, the plants lose their vegetative leaves (they turn
yellow and fall off easily), while the stem of the plant is lengthened.
The distance between the branches (also called the 'internode')
increases. When we just let the mercury-iodide lamps supply the plants
with blue light, this effect won't occur so easily. The supply of water
and nutrients continues. The time between irrigations is shortened, so
that the plants are still irrigated during each light cycle. Not in
order to push the plants to grow as fast as possible, but to keep the
metabolism at level, and to produce resins. The female plants will show
their first flowers after a week or two. The following period lasts at
least 60 days, depending on the variety. With some of the plants, the
blooming period lasts up to 90 days. It's worth the trouble to be
patient for the full flowering period before you start harvesting.
Harvesting during that time stresses the plants, which can ultimately
cause a decreased yield.
7.5. Harvesting and drying
In this book, we assume you've raised female cannabis plants from
clones. When you've sprouted male as well as female plants, there will
be some work sorting them out. The males flower earlier than the
females. If you leave the males with the females, the females will be
fertilized. The females then form seed, causing the tops to be smaller.
The yield is lower (why did we start growing in the first place?). If
you've sprouted males, you have to be sure to harvest them before the
pollen reaches the female plants. When you grow only females, you don't
have this trouble. There are various methods to harvest cannabis. Some
people cut the whole plant down, then hang it up to dry. Others break
the largest leaves off several days before harvest, so there will be
less waste. Hanging the plants, or the tops, upside down has no effect
on the THC content in the tops. The resin doesn't flow. What's important
with cannabis is the even drying of the THC-containig parts of the
plant. What's also important is patience. Generally, drying goes quicker
if you remove the stems which contain the most moisture. Using a
microwave, or an ordinary oven, a hair dryer, or a fan does make drying
faster, but usually also causes a (much) sharper taste. Even drying in
air prevents as much as possible the loss of THC, and produces evenly
dried buds with a soft taste. Controlling the climate also remains
important after the harvest. Many harvests have been lost due to spider
mites and mould. For the THC glands so important to us, light, heat, and
friction are the most important things to avoid. Once dried, cannabis
can best be kept air-tight in a reasonably cool, dark place. Air-tight
glass jars are ideal.
We'll talk about 'skuff'. This is the sifting of dried tops. When you
sift your dried harvest first through a rough, then through a fine
sieve, you remove all the remaining plant remnants, and get balls of
resin (thus; THC) left on the sieve. It's a fairly simple, but
time-consuming job. Sift the dried harvest first through a size T-44
sieve. The THC falls through (with a little extra material). We have a
T-77 size sieve under the T-44. You must carefully rub your harvest
through the T-77 sieve. Then you have THC in it's pure form without
7.7. Setting up the garden again
After the harvest, you must make sure you can literally start the
following growth with a clean slate. First remove all the leftover plant
parts. These go in the trash or in the organic waste, unless you have a
compost heap. Then remove all the rockwool material. The rockwool still
contains a lot of water.
old rockwoolslab in the wringer
Tip: see if you can use an old wringer, or a centrifuge. That will decrease the volume of the disposed rockwool by half. The following step is to disinfect the equipment. Any commercial disinfectant will do. Read the label to see how much to dilute it. Clean your irrigation system with disinfectant, and always thoroughly rinse afterwards. Possible calcium build-up on your humidifier should be removed. Cleaning lamps and reflective material is the next step. The lamp should be off, and completely cooled. Don't touch the lamp with your hands, because bodily acids can easily burn them. Result: shorter lamp life. Everything is now ready for the next growth. Lay out new rockwool material and wet it. It's time for new planting, so the timer clock goes back to 18 hours, and the irrigation to once every three hours.