The Difference Between Grow Lights & Blacklights


Grow lights, or "full spectrum" lights, and black lights are both types of electric light and both are generally based on fluorescent lighting technology although inadequate substitutes are available in other configurations. The fluorescent bulb is where the similarities end.

Black Light

Black lights emit long wave ultraviolet UV light and are used to charge phosphorescent or fluorescent paint or to illuminate certain chemicals, materials or fluids that glow in the dark when illuminated by UV light.

Grow Light

Grow lights emit light in the electromagnetic spectrum that best promotes photosynthesis. Grow lights mimic the light spectrum that comes from the sun. This allows horticulturists to grow plants indoors that need outdoor light.


Both black lights and grow lights also come in incandescent, LED high-pressure sodium and metal-halide versions, but none provide the full spectrum of light a fluorescent grow light does. Incandescent and LED black lights tend to give off too much visible light and not enough long wave UV light.

Black Light Safety

While short and medium wave ultraviolet light can damage eyes, ultraviolet light of the type emitted by black lights is safe for the eyes. Black lights operate at the 365 nanometer (nm) wavelength and use a 320 nm filter to prevent eye damage.

Grow Light Safety

Because sunburn occurs in the short and medium UV range (below 320 nm), grow lights pose no risk of skin or eye damage. Grow lights exclude damaging UV and infrared light altogether.


  • Glow Inc.: Black Light
  • Progressive Gardening: Plant Growing Lights
  • Terraponic Shop: Grow Lights
Keywords: Grow lights, black lights, grow black lights

About this Author

Tom King published his first paid story in 1976. His book, "Going for the Green: An Insider's Guide to Raising Money With Charity Golf," was published in 2008. He received gold awards for screenwriting at the 1994 Worldfest Charleston and 1995 Worldfest Houston International Film Festivals. He earned a Bachelor of Arts in communications from Southwestern Adventist College.

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