The Effect of Green Light on Plants


Different plants require different amounts of sunlight. Some like full sun while others prefer partial shade. But color is an important factor, too, especially if you're growing plants indoors under artificial light.

The Color Spectrum

A photon's wavelength determines its visible color. The longest wavelengths appear red, the shortest blue. Full spectrum light contains all different wavelengths, appearing white.

Reflection vs Absorption

Objects absorb some wavelengths and reflect others. Plants that appear green reflect green light while absorbing red and blue light.

Chlorophyll & Photosynthesis

Green chlorophyll is the substance chiefly responsible for absorbing light for plants to use in photosynthesis, the process by which they turn light into food. Chlorophyll cannot absorb green light, only red and blue.

Detrimental Effects of Green Light

Plants contain other pigments which can absorb slightly greener light and then pass this energy into the chlorophyll. Thus photosynthesis under green light is much less efficient, producing stunted, weakened, yellowish plant growth.

Beneficial Effects of Green Light

Nichele R. Lee's experiment comparing the effects of green and red lights on kidney beans showed faster germination under the green light.


  • ASU--Ask A Biologist: Seeing Color (Kim Cooper and C. J. Kazilek
  • Clermont College Biology Courses: Photosynthesis (J. Stein Carter)
  • Photosynthesis: What Color Light Helps Plants Grow? (Nichele R. Lee)

Who Can Help

  • BIOS 101 Lecture Material Online: Photosynthesis (University of Illinois at Chicago)
  • Photosynthetic Pigments (University of California Museum of Paleontology)
  • The Spectrum and Photosynthesis (University of the Western Cape, Botany Department)
Keywords: green light, visible spectrum, grow lamp, photosynthesis, chlorophyll

About this Author

Nicole J. LeBoeuf-Little is a freelance writer, blogger, and web designer from New Orleans, Louisiana. She is a graduate of the professional SF/F workshop Viable Paradise (2006). Recent published work appears at and, with a short story forthcoming at (March 2010).