Houseplants are labeled by the amount of light they need. Many are low- or medium-light plants. Those with colorful leaves often require full light while those with darker foliage are fine in less light. Since many plants in the home are evergreen, their light requirements remain fairly constant throughout the year. While providing the proper amount of light may be achieved with a nearby window in spring and summer, once the days begin shortening in winter plant lights may be needed to supplement natural light.
Choose a dual-light fixture and insert a cool-white and a warm-white fluorescent bulb. Alternatively, use a single grow-light bulb in a single-light fixture.
Supplement natural light by moving the plants under the grow lights once a day. Plants require twice as much artificial light as they do natural light, so a plant requiring six hours of sunlight and receiving three needs an additional six hours under grow lights.
Position the light so it is 4 inches above the plant and the light reflects on all sides. If plants are wider than the fixture, rotate the pot halfway through the lighting period to ensure all sides receive equal lighting.
Adjust the light distance for younger plants to maintain the 4-inch space between bulb and plant as it grows. Many fixtures are adjustable, otherwise stack a phone book or similar item under the pot to adjust the distance.
Plug the light into a timer set for the proper amount of time. Timers ensure plants receive enough light even if you forget to turn them on or off.
Check moisture levels in the pot weekly by sticking your finger into the soil. Water only when the top inch of soil feels dry. Plants grown under lights may be more prone to soil fungus from poor lighting conditions. Too much water increases the chances for fungus.