found some stuff on lighting that might be of use to some of the new grower .knock yourselfs out lads and lassies.
Plants use light as energy to fuel photosynthesis, a process in which water and carbon dioxide are converted to sugar. Sugar is the basic building block of all plants. Without light, green plants have no way of producing food and they die.
By chemically twisting and tweaking the sugar molecule, plants form carbohydrates, which are more complex molecules. With the addition of nitrogen, amino acids are formed. These group together to form proteins, the building block of the tissue.
Indoor gardens require electric lights to power the plants. Since marijuana is a sun-loving plant, it requires a high intensity to grow and thrive.
LIGHT SPECTRUMS AND PHOTOSYNTHESIS
To produce chlorophyll, plants need light from specific spectrums, mainly red and blue light. This is called the chlorophyll spectrum. Chlorophyll uses a slightly different spectrum of light to power photosynthesis the process that results in sugar production.
Plants use red and blue light most efficiently, but they also use orange and, to a lesser extent, yellow light. Plants are continually growing as well as producing new chlorophyll, so both spectrums of light are continually being used by the plant. Plants reflect green light rather than absorbing and using it.
Each source of light has a characteristic spectrum that is caused by varying wavelengths of light. To our eyes, midday summer sunlight looks neutral, incandescent lights have a reddish tint, fluorecents vary in spectrum according to their type, metal halide (MH) lamps have a blue coolness to them, and high-pressure sodium (HPS) lamps look pink-amber.
TYPES OF LIGHTS
FLUORESCENTS
Until the early 1980s, most indoor growers used fluorescent tubes for budding as well as cloning and early vegetative growth. These tubes have tremendous advantages over screw-in incandescent lights. A flourescent emits about three-to-five-times as much light as an incandescent of the same wattage.
Standard fluorescents, such as the four-foot tubes, have their limitations. Light is emitted over a large area, the entire surface of the tube, so it is not concentrated. The tubes are bulky, so only a limited amount of light can be delivered to a given area. The fixtures are usually placed within inches of the plants, so that the light does not spread and become less intense. When the light fixtures are hung, they are hard to manipulate, making it more difficult to tend the garden.
Fluorescents have their uses. They are the best lights to use for cloning and early vegetative growth and are sometimes used in small gardens. They are no longer limited to bulky fixtures, so they can be used to supplement other light.
Houseware stores sell many types of screw-in fluorescents for incandescent fixtures. These bulbs come in several shapes, including circles and u shapes. They are covvenient because they are compact and can easily be placed around the garden.
Gardens lit by fluorescents require an input of at least 30 watts per square foot to produce vigorous plants and good bud This comes to three tubes for each foot of width if regular fluorescent four-foot or eight-foot tubes are used. With the new screw-in fluorescents, which use compact tubes, the lamps can be placed close together to provide higher intensity.
The inner surface of each fluorescent tube is covered with a phosphor that glows when it is stimulated by the flow of electrons through it. Fluorescent tubes are named for the spectrum of light that they emit. For specific periods of plant growth, some spectrums are more conducive to growth than others.
FLUORESCENTS FOR ROOTING AND VEGETATIVE GROWTH
During the rooting and vegetative growth stages, plants grow shorter, stockier stems when they are grown under a "cool" lamp such as cool white shop-lite, cool white, or other tubes with "cool" in their names, which denotes that they are high in the blue spectrum.
Probably the best fluorescent light for cloning and vegetative growth is the GE Chroma 5000, or a tube with similar specifications. It is very high in blue-spectrum light and is about 20% brighter than standard tubes using the same amount of electricity.
While cuttings are being rooted, only one tube per foot of width, (about nine watts per foot squared), is needed to maintain the plants. Once the plants have roots, they require more light to grow compactly. While they are still in the vegetative growth stage, they can get by on 20 watts per foot squared, but grow faster if they receive about 30 watts.
"Full spectrum" fluorescents, such as vita-lites, emit a light balance close to suns spectrum. Many growers swear by these lights and use them for all stages of growth.
During vegetative growth; avoid warm white tubes, tubes with "warm" in their names, or tubes that emit a warm glow. These will promote stretching and premature flowering.
Some manufacturers produce fluorescent grow tubes formulated to provide a light spectrum similar to the chlorophyll synthesis or photosynthesis or a compromise between them.
Grow tubes can be used for cultivation, alone or in combination with other tubes. Although they produce less total light, some of them emit more light that is usable by the plants than standard tubes. During vegetative growth, use the wide-spectrum grow tubes or tubes with a pink (rather than purplish) light. These have more blue and less red than the others, promoting stocky stems and short internodes.
FLUORESCENTS FOR FLOWERING
During flowering, the plants can use a lot more red light than they can during vegetative growth. Fluorescent tubes suitable for this stage of growth are warm white and warm white deluxe tubes,
fluorescents with "incandescent" spectrums, and compact lights with a warm or reddish glow.
The GE Chroma 3000 or a tube with similar specifications is an excellent four-foot or eight-foot tube that promotes flowering and fast ripening. However, some screw-in fluorescents have more red which promotes flowering and ripening.
CARING FOR FLUORESCENTS
As fluorescent tubes age, they become less efficient. On the average, they lose 25% of the light they were rated for after a year of use. They should be replaced so that the garden stays bright. Lights that are turned on and off a lot wear out faster. Three-inch to six-inch sections on both sides of the tube dull out from deposits after a short term of use. The effective length of a four-foot tube is three feet, eight inches and that of an eight-foot tube is seven feet.
FLUORESCENT LIGHT REFLECTORS
Fluorescent tubes come in many lenghts, but the two most commonly used by indoor gardeners are four-foot and eight-foot. They are convenient and more effcient than other sizes.
Most fluorescent fixtures are poorly designed, with no baffles between the individual tubes to reflect light downward. They lose up to 40% of the light. Instead, if possible, the tubes should be mounted on a reflector with baffles between the tubes so that light is directed downward to the garden. A good reflector keeps the light loss down to 20%. These fixtures cost a little more, but save money in the long run because of the light they save.
An alternative is to use tubes with reflective surfaces, which are made by several manufacturers. Housewares and lighting stores do not usually carry them, but will special-order them.
HIGH-INTENSITY DISCHARGE LAMPS
High-intensity discharge lamps (HIDs) are more convenient and more efficient than fluorescents. Low-wattage HIDs are sometimes sold in houseware stores and are often convenient to use in small gardens. High-wattage systems are sold in grow stores and garden shops.
HID lights are powered by heavy ballasts (400-watt-28lbs.,1000-watt-40lbs), which are usually connected to the light by a long electrical wire. Some 400-watt HID systems are manufactured with the ballast built into the same housing as the reflector. These lamps are harder to move around and are usually considered for lighting only if they are to be permanently mounted.
HID lighting systems are much more convenient to use than fluorescents because the lamps are not nearly as bulky as banks of fluorescents. HIDs also have higher wattages and are more efficient at producing light than fluorescents.
