Can a Cool White Bulb Grow My Plant?

Plants require the full spectrum of visible light.

For those interested growing plants indoors or those wishing to supplement low levels of natural light with artificial light, a combination of cool white bulbs and traditional incandescent bulbs is best.

Cool Bulbs Vs. Hot Bulbs

Cool bulbs, or fluorescent bulbs, give off light in wavelengths on the blue side of the spectrum. Hot bulbs, or incandescent bulbs, emit wavelengths on the red side of the visible spectrum of light.

What to Use

In the absence of the appropriate combination of red to blue light, a cool white bulb would provide about 70 percent of the needed light for a plant to grow. Ideally, supplement the other 30 percent with an incandescent bulb.

How to Use

When using artificial lighting, don't place bulbs more than 24 inches away from the tops of the plants. The energy released from bulbs placed further away will diffuse before reaching the plants and be of little use. Adjust the positions of the bulbs as the plants grow.

References

• Clemson Cooperative Extension; Indoor Plants - Cleaning, Fertilizing, Containers and Light Requirements; Debbie Shaughnessy, et al.; September 1999
• University of Wisconsin: Kenosha Extension; Seed Starting Lights; February 2011
• Oregon State University Extension Service; Houseplants Can Thrive In Low Winter; Judy Scott; 1995 Light
• Colorado State University Extension; Houseplants: Artificial Light; October 2010