Section 3: Choosing Lighting

Since there is no sun in your closet you will have to provide a sun loving plant like marijuana with a lot of artificial light. There are three options available to the grower: fluorescent lights are cheap, efficient, and don't put out much heat. Metal halide, or MH bulbs, are more expensive but put out much more light than fluorescents. They also put out more heat so ventilation is needed. MH bulbs also require a separate ballast in order to work. High Pressure Sodium lamps, or HPS, put out as much light as MH lamps but with a little less heat. Ventilation and a separate ballast are also required.

Fluorescent lights

Fluorescent lights are the cheapest light to use. They run at about $2 a tube. They produce little heat so ventilation may not be needed unless the space is very small. The light spectrum put out by these lights is suitable for all stages of growing. Because fluorescents disperse light over a large area, they need to be kept within three inches of the tops for the plants to receive enough light. This means you will have to mount the lights in a way that the can be raised everyday.
Metal Halide Lights

Metal halide lamps put out the most light. They also produce alot of heat. A strong fan is needed to keep room temperatures down. MH lamps put out light mostly in the blue spectrum. Blue light is used best by the plant during vegetative growth. MH lights can also be used for flowering with no adverse effects. A separate ballast is required for these lights to work. They come in sizes from 40 to 1000W. One 1000W lamp will provide enough light in a closet to grow four plants.
High Pressure Sodium Lights

High pressure sodium lamps put out almost as much light as MH and with less heat. Good ventilation is still required though. HPS lamps produce light in mostly the red and orange end of the spectrum. The plants uses this light best when flowering. HPS lamps can also be used for vegetative growth with little slow down in foliage production. HPS lamps require a separate ballast for operation.

Some growers switch between MH and HPS depending on what stage the plants are in. MH is used in vegetative growth and then the light is switched over to HPS once flowering begins. Most growers use fluorescents to start seedlings and root clones. The fluorescents are weaker than the MH and HPS lamps and therefore do not stress them too much. Choose whatever light is best suited for your situation. If your are growing in your attic go with MH or HPS. If your growing in the closet like us, then use fluorescents. (For the rest of ths document I will assume the reader is using fluorescent lighting)