Does a Plant Light Mimic the Sun's Rays?

The proper light is essential for growing plants successfully indoors. Although most plants prefer natural light, indoor plants will also grow well if provided with electric lights that closely mimic the spectra of natural sunlight.

Best Light Colors for Plants

Each color of light in the visible spectrum corresponds to a different wavelength, and certain wavelengths are more important than others for plant growth. Plants require light in the red and blue wavelengths for healthy growth and derive little energy from yellow or green.

Types of Plant Lights

The most commonly used lights for growing plants indoors are fluorescents, which offer the best compromise between price, light output, heat and power consumption. High-pressure sodium, metal halide, and LED bulbs will work as well, but they are much more expensive and less efficient than fluorescents. Incandescent bulbs are a poor choice for plant growth, because they generate excess heat and emit light rays of the wrong color.

Plant Light Usage

Plants without access to sufficient natural light will grow best indoors when provided with fluorescent illumination, especially bulbs with higher output in the red range. The amount of light required is different for each plant, but as a general rule, plants with low to medium light requirements will do best indoors. Light sources should be positioned approximately one foot away from plants and lit for 16 to 18 hours each day.

References

• University of Missouri Extension; Lighting Indoor House Plants; David Trinklein; 2002
• University of Vermont Extension; Indoor Lighting for Plants; Dr. Leonard Perry
• University of Hawaii at Manoa; Tropical Plant and Soil Sciences Department; Growing Plants Under Indoor Lighting; Kent Kobayashi