Plants require an appropriate blend of light colors and light intensity for healthy plant growth. Many plants also require a set number of hours of light to grow and flower. A combination of light from a cool white fluorescent tube and incandescent bulb is optimal. Warm-white fluorescent tubes can be fairly effective, but fluorescent tubes listed as white or daylight are less desirable for indoor plant growth.
The incandescent light should account for 30 percent of the wattage, and the fluorescent tube 70 percent. For example, use two 40-watt cool-white fluorescent tubes and one 40-watt incandescent bulb. Alternatively, use a light bulb designed for house-plants such as Agrolite, Vitalite, Gro-Lux or others. Many indoor gardeners use cool-white fluorescent tubes.
The light in most homes often is not bright enough to grow house-plants properly. Yet some houseplants thrive in low light if they are kept out of dark corners. Aluminum plants, pepperomia, ferns, palms, snake plant and some philodendrons can survive in low-light areas. Most houseplants need additional light to survive over a long period of time in the average home. Older plants shed or lose a large number of their leaves when sufficient light is not provided. New leaves that develop under low light conditions are usually smaller and thinner than leaves growing in normal light, but are acclimated to low light conditions.
Commercially available plant grow lights and homemade light fixtures provide light typical of a north-facing window during daytime. This type of light is adequate for most bromeliads, jade plants, scheffleras, certain succulents, zebra plants, spider plants, grape ivy, dumbcane, wax plants and some ferns. Nine to ten hours of artificial light per day is adequate for most houseplants.