Plants need light to grow, but not just any light will do. The quality of light can affect a plant's performance. Plants grown under poor lighting conditions may produce poor, spindly growth. Flowering and fruiting plants also need light of a specific intensity for a specific amount of time in order to produce abundant flowers and fruit.
Color-Balanced Fluorescent Tubes
White light, such as the kind emitted by the sun, is made up of a blend of every color in the rainbow. Each of these colors has a specific wavelength. Most fluorescent lights emit these colors in different intensities. This is why fluorescent light has a colored tone to it. Plants absorb red and blue wavelengths of light better than green and yellow light wavelengths. Red and blue tubes designed for plants are built to emit more light in the blue and red spectrums and less in the yellow and green.
Cool White Fluorescent Tubes
Although plants primarily use the light in the red and blue spectrums, they also need light along the other spectrums of color as well for complete nourishment. Cool White fluorescent tubes produce light along orange and yellow-green spectrums in addition to blue and red. According to the University of Missouri, Studies show that a mixture of cool white and color balanced fluorescent tubes make the most efficient lighting for indoor plants and will promote the best display of flowers.
High Wattage Fluorescent Lights
The intensity of a plant's light will also affect a plant's performance. Plants that grow close to their light sources receive more intense light than plants grown a great distance away from a light source. Fluorescent lighting is superior to incandescent light bulbs because it puts out less heat. This allows gardeners to use lighting more efficiently by placing their plants closer to the light source. For example, a plant that is placed 1 foot away from an exposed fluorescent fixture that holds two standard 40-watt light tubes will receive 260-foot candles of light. A plant placed 2 feet away from this fixture will receive 110-foot candles of light. Lighting intensity is most important for flowering plants because many of these plants are phototropic. Phototropic plants require between 11 and 14 hours of darkness nightly. Owners of poorly-lit plants will often leave plant lights on for 16 hours daily to compensate for the poor quality of light the plants are receiving. If a phototropic plant is grown under these lighting conditions, it will not flower. High-output fluorescent lights placed on a timer will give plants the proper lighting for the proper duration and will promote flowering.