Lighting and Lights

BobNarley · 05-30-2008, 09:54 AM

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 Optimizer® 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
2½ 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 2½ 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' '® 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.

BobNarley · 05-30-2008, 09:56 AM

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 ¼ 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 ½ 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, 1½ 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 ½ 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.

05-30-2008, 09:54 AM	#1 (permalink)
BobNarley My Mood: Join Date: May 2007 Location: Mojove Desert-Southern California Posts: 530 gRamz: 13,397 Danks: 26 Danked 17 Times in 14 Posts	Lighting and Lights 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 Optimizer® 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 2½ 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 2½ 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' '® 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.

05-30-2008, 09:56 AM	#2 (permalink)
BobNarley My Mood: Join Date: May 2007 Location: Mojove Desert-Southern California Posts: 530 gRamz: 13,397 Danks: 26 Danked 17 Times in 14 Posts	Carben Dioxide 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 ¼ 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 ½ 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, 1½ 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 ½ 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.

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