Types of Lights for Cannabis Growing - Different Marijuana Lighting Sources
Light for cannabis plants
Without light, cannabis plants cannot grow. In the countries in which marijuana grows best, the sun is the source of light. The amount of light and the length of the growing season in these countries results in
huge tree-like cannabis plants. In most parts of
North America, however, the sun is not generally intense enough for long enough periods of time to produce the same size and quality of cannabis plants that grow with ease in
Latin America and other
tropical countries.
Sunshine is most intense at the equator where it is closest to the earth.
Some of the largest, resin-coated buds in the world grow beneath this
blazing sun. So what’s this got to do with indoor growing? Plenty.
Light is one of the most basic needs of all cannabis plants and the most often mismanaged.
Even the most experienced growers forget about the
basic needs of a cannabis plant, especially
light.
The answer to the problem of lack of sun, especially in the winter months, shortness of the growing season, and other problems is to grow indoor under simulated conditions.
The rule of thumb seems to be
the more light, the better.
The common incandescent light bulb emits some of the frequencies of light the cannabis plant can use, but it also emits a high percentage of far red and infra-red light which cause the cannabis plant to concentrate its growth on the stem. This results in the cannabis plant stretching toward the light bulb until it becomes so tall and spindly that it just weakly topples over.
There are several brands of bulb type. One is the incandescent cannabis plant spot light which emits higher amounts of red and blue light than the common light bulb. It is an improvement, but has it drawbacks. it is hot, for example, and cannot be placed close to the cannabis plants.
Consequently, the cannabis plant has to stretch upwards again and is in danger of becoming elongated and falling over. The red bands of light seem to encourage stem growth which is not desirable in growing marijuana. The idea is to encourage foliage growth for obvious reasons.
Flourescent light tubes range in size from one to eight feet in length so you can set up a growing area almost anywhere. There are two types of flourescent lights; standard and the wide spectrum. They can be used in conjunction with one another, but the wide spectrum lights are not sufficient on their own. The wide spectrum lights were designed as a supplementary light source and are cheaper than the standard lights.
Wide spectrum lights emit the same bands of light as the standard but the standard emit higher concentrations of red and blue bands that the cannabis plants need to grow.
The wide spectrum lights also emit infra-red, the effect of which on stem growth we have already discussed. If you are planning to grow on a large scale, you might be interested to know that the regular fluorescent lamps and fixtures, the type that are used in commercial lighting, work well
when used along with the grow lights.
These commercial lights are called cool whites, and are the cheapest of the fluorescent lights we have mentioned. They emit as much blue light as the standard grow lights and the blue light is what the cannabis plants use in foliage growth.
Intensity
Now we come to the question of intensity. Both the standard and wide spectrum lamps come in three intensities: regular output, high output, and very high output. You can grow a crop of cannabis plants under the regular output lamps.
The difference in using the HO or VHO lamps is the time it takes to grow a crop.
Under a VHO lamp, the cannabis plants grow at a rate that is about three times the rate at which they grow under the standard lamps. People have been known to get a cannabis plant that is four feet tall in two months under one of these lights.
Under the
VHO lights,
one may have to raise the lights every day which means a growth rate of ate least two inches a day. The only drawback is the expense of the
VHO lamps and fixtures. The
VHO lamps and fixtures are
almost twice the price of the standard.
Now that you have your lights up, you might be curious about the amount of light to give you cannabis plants per day. The maturation date of your cannabis plants is dependent on how much light they receive per day. The longer the dark period per day, the sooner the cannabis plant will bloom. Generally speaking, the less dark per day the better during the first six months of the cannabis plant's life.
If your cannabis plants receive 12 hours of light per day they will probably mature in 2 to 2.5 months. If they get 16 hours of light per day they will probably be blooming in 3.5 to 4 months. With 18 hours of light per day, they will flower in 4.5 to 5 months. Its a good idea to put your lights on a timer to ensure that the amount of light received each day remains constant.
How the Sunlight Effects cannabis plant Growth
200 - 280 nm
UVC ultraviolet range which is extremely harmful to cannabis plants because it is highly toxic.
280 - 315 nm Includes harmful
UVB ultraviolet light which causes cannabis plants colors to fade.
315 - 380 nm Range of
UVA ultraviolet light which is neither harmful nor beneficial to cannabis plant growth.
380 - 400 nm Start of
visible light spectrum. Process of
chlorophyll absorption begins. UV protected plastics ideally block out any light below this range.
400 - 520 nm This range includes
violet, blue, and green bands.
Peak absorption by chlorophyll occurs, and a strong influence on photosynthesis. (promotes vegetative growth)
520 - 610 nm This range includes the
green, yellow, and orange bands and has
less absorption by pigments.
610 - 720 nm This is the
red band.
Large amount of absorption by chlorophyll occurs, and most significant influence on photosynthesis. (
promotes flowering and budding)
***
720 - 1000 nm *** There is
little absorption by chlorophyll here.
Flowering and germination is influenced. At the
high end of the band is infrared, which is heat.
1000+ nm
Heat
Marijuana Lighting Tips
Although natural sunlight is the best form of light for growing cannabis plants, their life cycle can be controlled more effectively with artificial lighting
The life cycle of the cannabis plant is determined by the daily photoperiod (
hours of light per day).
A young cannabis plant tends to grow faster if it is grown under continuous light for the first two months of it's development.
Although the lamps should be kept as close as possible to the growing leaves, they should never be allowed to touch the cannabis plants.
The best light for cannabis plant growth emits high intensities of the blue and red bands of the light spectrum.
Fluorescent light is one of the most effective source of artificial light readily available to home growers.
Metal Halide lamps are better than
most fluorescents,
because they radiate more light in the blue and white bands of the light spectrum.
If your lights are too hot to touch with your hand, they are probably also too hot to be close to the growing leaves of cannabis plants.
The amount of light you supply your cannabis plants depends on the size of the garden, but
at least 20 watts per square foot is recommended.
Although Metal Halide lamps are generally considered a better light source for marijuana growth, they use a lot more electricity than fluorescents..
Under artificial light, a cannabis plant can grow from three to six feet tall in three to four months.
cannabis plants entering the vegetative stage enjoy up to twenty two hours of light per day, while twelve hours or less is required for flowering.
The more light you give your cannabis plants, the faster they will grow.
Lamps should be fixed to the roof in such a way that they can easily be raised as the cannabis plant grows in height.
The use of reflectors ensures that the light is spread more uniformly around the cannabis plants.
To increase the humidity of the air in a small, enclosed garden, place a small bowl of water in the grow room.
Use a fan to cool down your cannabis plants if the lights in a small grow room raise the temperature too much.
cannabis plants grown in conditions of varying daily light patterns will not settle into a regular life cycle and will grow poorly.
If there is insufficient light in the grow room, the cannabis plants will often grow tall and thin, in search of the light.
Do not "wake up" your cannabis plants by switching on the lights if they are in the dark period of their daily light cycle.
cannabis plants grown with a long daily photoperiod, will require more frequent watering than those grown with less light.
Although incandescent, or screw-in light-bulbs are usually not suitable for good growth, they can be used in conjunction with fluorescent tubes.
If the edges of the leaves near the lights and growing tips start curling up, it usually means that they are getting too hot.
A cannabis plant will grow with as little as six hours of light per day, but requires more than twelve hours per day for good strong growth.
A cannabis plant grown with insufficient light may sometimes develop disfigured leaves with only one or two blades per leaf.
Paint the walls, floor and roof of your grow room white for better reflection of light onto your growing cannabis plants.
If you have a few cannabis plants growing unevenly under one light, you could raise the pots of the smallest cannabis plants by placing them on a few bricks.
Although easy to control, the daily light photoperiod is the single most important factor influencing the growth of your cannabis plants.
cannabis plants require less than twelve hours of light per day for at least two weeks before you can expect to see the first signs of flowers appearing.
Never increase the daily light photoperiod to more than twelve hours, once your cannabis plants have started flowering.
A cannabis plant grown indoors with lots of light will often grow larger and more potent than a similar cannabis plant growing outdoors in natural light.
To increase the amount of light available to the lower branches, you could mount extra fluorescent tubes vertically, onto the walls of your grow room....
Or
Do what I do and hang a Full Spectrum Lighting Rig and configure the colour dependant on whether in Veg or Flower
I got this info from
http://www.weedfarmer.com/cannabis/lights.php most of it is helpful and of good info too, I found it through chance on a
Google Search
Anyway.. at least I can see that I
wont need Infra-Red light since it concentrate on the stem and makes them spinderly... No Grower wants that lol.. so once I have the
KESSIL Iam pretty certain I will have the
Full Spectrum I so desire
- STELTHY