Artificial lighting is useful for starting seeds indoors or for growing plants during winter months or year round. The best light to use depends on the usage and the plants to be grown. For starting seeds indoors and for short term use, fluorescent bulbs will work. For year round growing, a light source providing a balance of both blue and red light wavelengths is needed. Mixing cool and warm fluorescent wavelengths will work. More expensive metal halide lights provide the wavelengths needed by plants during the leafy vegetative stages. High pressure sodium lights provide the wavelength balance needed by plants during the flowering stage.
Choose the best lights for your situation. Choose lights that produce both red and blue wavelengths.
Build or purchase a framework or shelving system to suspend the lights above the plants. Lights can also be mounted on the sides. The lights should be moveable to provide room for the plant to grow.
Locate the lights as close to the plants as possible without burning the leaves. Hold your hand at the height of the top of the plant to be sure the plants are not getting too much heat.
Arrange mirrors or reflectors to focus the light onto the plants.
Locate low light plants at the outer edges of the lights and high light plants at the center, directly under the lights.
Move the lights up as the plants grow so that the light is as close as possible but never close enough to burn the plant.
Set the lights on a timer to provide 16 to 18 hours of light a day. Reduce light to 12 hours, if needed, to induce flowering.
Provide an exhaust fan to remove heat from the room if needed. Lights give off a lot of heat, and cooling may be needed in intense lighting situations with lots of plants.