Can Orchids Live in a Compact Fluorescent Light (CFL) Environment?

In the wild, orchids typically grow in humid jungles under a canopy of trees. You can recreate this bright, indirect sunlight in a home environment by using artificial light sources, such as compact fluorescent lights (CFL). However, this type of lighting, which is much more affordable than other types, has a different effect on plants than the more traditional incandescent (INC) lamps.

Orchids can thrive under fluorescent lighting -- and CFL lights emit the exact same type of light. The only difference is the shape of the lights. CFL lamps are often coiled into bulbs, saving space and allowing you to place them in normal-sized light fixtures. Like fluorescent lights, they come in several types, such as full-spectrum, warm or cool, with full-spectrum being the smartest choice for orchids because its color composition is closest to natural sunlight's. Because they don't emit as much heat as INC lamps, they are less likely to burn foliage even when placed within a few inches of orchids. They are also more efficient than INC lamps, which means you'll use lower wattage with FL and other fluorescent lights than you would using INC lamps.

Some types of orchids are better suited to a CFL environment than others. Orchids that appreciate low or medium light are the ones that typically thrive under CFL lamps. For instance, Phalaenopsis, hardy outdoors in U.S. Department of Agriculture plant hardiness zones 10 and 11, can grow under four 60-watt CFL bulbs positioned no more than 4 inches above it. However, high-light orchids such as the Vanda, also hardy in USDA zones 10 and 11 outdoors, typically require stronger lights, such as high-pressure sodium lights or metal halide lights that emit more intense light, especially cool blue and warm red light, respectively.

You can adjust artificial lights so that they are as similar to natural sunlight as possible. Specifically, you need to concentrate on the red (R) to far-red (FR) ratio of lights -- and CFL lamps don't emit as much FR light as INC lamps. To emulate the R:FR ratio of sunlight, you should put orchids under an equal number of each type of lamp, so that CFL lamps emit 50 percent of the light and INC lamps emit the other 50 percent. This creates a R:FR ratio of 0.9 -- almost the same as natural sunlight's.

To ensure that the CFL lamps supply intense-enough sunlight for optimal orchid growth, place them within 12 inches of your orchids -- closer is usually better, depending on the type of orchids you're growing and the wattage of the CFL bulbs. However, keep at least 2 to 4 inches between your orchid and its light source for aeration and to prevent the orchid from burning. You can keep the lights on for as long as the natural daylight remains outside, or give your orchid a 16-hour day during the growing period, reducing light hours to about 14 hours in winter. Always provide your orchids with at least six hours of darkness each night, as this is necessary to induce blooming.