What Type of Light Makes Plants Grow Bigger: Fluorescent or Incandescent?


Artificial lights are a stable way to grow plants indoors year-round. Though both incandescent and fluorescent lights can be used for growing plants, fluorescent lights are indisputably the better choice.

Light Spectrum

Incandescent lights emit mostly red rays and not many blue rays. This means that plants cannot get the entire light spectrum they need. Fluorescent lights emit both blue and red light, which provide your plant with all it needs to grow. Red light particularly encourages flowering in plants, and blue light encourages full plant growth. To make your plants grow bigger, the full spectrum offered by fluorescent lights will do it.


Incandescent lights must be placed far from the plant because they emit so much heat they will damage the plant if too close. Fluorescent lights emit less heat, so they can be placed within inches of the plant, and the intensity of the light received by the plant is greater.


Incandescent lights are only one-third as efficient as fluorescent tube lights, according to David Trinklein of the Department of Horticulture at the University of Missouri. This means fluorescent bulbs emit more light using the same amount of electrical energy. This efficiency is good for your plants, your wallet and your environment. Fluorescent lights also need to be replaced less often during the life of your plant, since they last much longer than incandescent lights.

Fluorescent-Incandescent Combination

Incandescent lights used alone are not enough to grow indoor plants because they emit mostly red rays. However, many fluorescent lights emit more blue than red rays, so a combination of both kinds of light is actually the best choice for your plants. Use a ratio of 3 to 10; for every 30 watts of incandescent light, provide 100 watts of fluorescent light.

Fluorescent Grow Lights

If you decide to use only fluorescent lights, check that they provide all the red rays your plant needs. Fluorescent "grow lights" emit more red rays than traditional fluorescent lights; these grow lights can be substituted for incandescent lights to avoid the hassle of buying fixtures for both kinds of bulbs. Grow lights can be used alone or with an equal number of cool-white fluorescent bulbs (the best kind of fluorescent light for growing plants).

Keywords: fluorescent light, incandescent light, plants

About this Author

Meg MacKenzie has been writing professionally since 2010. Her articles have been published on eHow, where she specializes in liberal arts and lifestyle topics, including fashion, relationships and interior design. She graduated with a Bachelor of Arts in English and classics from the University of Connecticut in 2009.