Ultra Violet (UV) light plays a significant role in all aspects of plant growth. Plants, in their natural environments, are exposed to natural sunlight which includes UVA and UVB light. Many of the lights used for indoor plant growth produce very small amounts of UV and some produce none at all.

Vegetable seedlings in tray

Think of what happens to your skin when you are exposed to sun for long periods of time. It begins to burn and sweat. Plants are no different. UV light activates a plant’s defense mechanisms. UV causes plants to produce oils, antioxidant vitamins and flavonoids to protect themselves from the damaging effects of UV.

These compounds produce the vibrant colors, smells and tastes of your plants. If your light source does not produce UV, you are effectively changing the color, smell and taste of your crop.

Keep in mind traditional lighting measurements such as Lumens, PAR and Kelvin temperature do not measure UV. Only a UV meter or a spectral distribution chart can provide information on a light source’s UV output.