Artificial Light & Plant Growth


Many homeowners use houseplants to add interest and color to their rooms. However, indoor environments rarely suit plants that need many hours of natural light each day. Even plants kept in windows sometimes do not receive enough light, and plants do not grow or flower as a result. Artificial lighting could be the trick to revitalizing your houseplants.


Plants do not obtain energy from food; instead, they produce their own energy using sunlight. This energy powers the plant's growth and development. In addition, the different wavelengths of light to which plants are exposed outdoors affect different aspects of growth. Red light encourages flower and seed production, while blue light influences the growth of leaves and stems. In order to thrive indoors, plants need to receive enough light and the proper kind of light.


Incandescent and fluorescent lights are most commonly used in the home, according to the University of Missouri Extension. Incandescent lights provide an abundance of red light but very little blue. The extension recommends fluorescents as the best source of indoor lighting for plants. However, because they provide little red light, a balance of incandescent and fluorescent may be needed. Sodium-vapor and metal halide lights also work well, although they are more difficult to find for home use.


Plant species vary in the amount of light that they prefer to receive, although the University of Missouri Extension points out that it is impossible to provide too much light by correctly using incandescent or fluorescent lights. However, some plants, such as orchids and poinsettias, do require a certain amount of darkness each day in order to flower. The Alberta government's Agriculture and Rural Development Agency advises that most plants thrive with 14 to 18 hours of light per day. Homeowners should make adjustments based on those guidelines for plants with special requirements.

Expert Insight

Providing plants with both incandescent and fluorescent light ensures that they receive adequate amounts of both red and blue light at an adequate intensity. The University of Missouri Extension recommends providing incandescent and fluorescent lighting in a 3-to-10 ratio. For example, for every 30 watts of incandescent, provide 100 watts of fluorescent lighting.


One of the problems with incandescent lighting is that it produces large amounts of heat in addition to light that can harm plants and cause the leaves to wither and curl. However, because the light is not intense, too much distance may mean that plants aren't receiving enough light. Keep adequate distance between incandescent lights and plants, assuring a good supply of light without burning plants. The Alberta Agriculture and Rural Development website recommends keeping incandescent lights a foot to 16 inches above plants.

Keywords: indoor plant lighting, lights for houseplants, growing plants indoors, houseplant artificial light

About this Author

First published in 2000, Dawn Walls-Thumma has served as an editor for Bartleby and Antithesis Common literary magazines. Her work has been published academically and in creative journals. Walls-Thumma writes about education, gardening, and sustainable living. She holds a Bachelor of Arts in psychology and writing from University of Maryland, and is a graduate student in education at American Public University.