As LED technology continues to evolve and increase in power density, UV LED lamps are expanding into the market and replacing more traditional alternatives.
UV light appears between the visible and X-ray spectra. UV is named for the "purple" color it produces in the visible part of the spectrum, although most of the UV output is not visible to the human eye.
Lighting can pose the greatest obstacle when trying to grow plants successfully indoors, especially if you don't have a window that lets in plenty of sunshine. Plants require more time in the light when grown under plant lights, but determining how much depends on individual plant needs, the light intensity and the type of lighting you provide.