Ultraviolet rays are used only in small quantities and can easily damage plants. They give off a large amount of red light and infrared radiation, most of which becomes heat. This causes cooling problems and burning of leaves. Because the fight source is concentrated in a small area, light distribution is likewise restricted to a small area. Fluorescent lights have a higher light efficiency than incandescent lights. emitting two and a half times as much light per watt.
Fluorescent tubes vary in red-blue output.
A combination of cool white and warm white is recommended for use on house plants. Most house plants can be grown under fluorescent lamps alone, although it is a common practice to mix incandescent and fluorescent light in the ratio of two or three florescent lamp watts to one incandescent lamp watt. This provides the proper light quality without excessive heat. Daylight, warm white, and natural white tubes can also be combined in various ratios to provide a suitable quality for plant growth. However, it is the quantity and brightness of light that is most important, not the quality of the light.