This is an artificial light source that helps plants grow when there is not enough natural light. These lights attempt to provide a spectrum of light similar to what the sun provides. Orchids & African Violets can be encouraged to bloom all year & herbs and salad greens can be grown indoors. Different plants require different light spectrums. Natural sunlight provides the full spectrum of yellow through violet that plants need for photosynthesis. Red is best for encouraging flowers and vegetative growth and blue helps regulate strong foliage growth. Just as with color spectrums, different plants need varying degrees of light intensity. The wattage & how close the light is to the plant determine the intensity. Some plants need to be 10”-12” from the light, others can be 36” away. Plants need a rest period, so lights shouldn’t be left on all of the time. There are three main light categories: short-day plants need about 12 hours of light; day neutral plants need 8-12 hours; long day plants need 14-18 hours. Many types of grow lights are available: Fluorescent lights are the cheapest & produce 2-3 times more light than the incandescent. Full-spectrum fluorescent produce a balance of cool & warm light that mimics the sun. Metal halide lights emit an intense, bluish-white light & seem to be the most popular grow lights used today. The high pressure sodium variety produce a yellow-orange color that convinces plants to produce fruit & flowers. LED grow lights are relatively new inexpensive, bright, long-lasting lights that produce less heat & use less electricity.(Wikipedia/Gardener’s Supply Co.)