Do Plants Need UV & IR Light All The Time?

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Everyone knows that only LED grow lights with full spectrum can help plants grow healthily. When it comes to full spectrum, in addition to its own meaning, two controversial concepts are mentioned more and more frequently, namely Ultraviolet and Infrared.

What UV and IR light are.

Ultraviolet Light (UV) Ultraviolet light is a type of electromagnetic radiation that comes from natural sunlight. This light is broken up into three different sections of different wavelengths: UVA = 400nm-315nm UVB = 315nm-280nm UVC = 280nm-100nm

Far-Red and Infrared Light On the far end of the spectrum (>700nm) you find far-red and infrared wavelengths of light. Far-red and infrared light have very long wavelengths, and very little energy. Infrared wavelengths are not visible to the human eye and only can be felt as heat. 

The Benefits of UV and  IR light.

UV has been shown to increase the amounts of THC, CBD, and terpene production in cannabis plants. UV light is extremely important for plant growth too. In safe doses, UV helps produce oils that create the great smells and tastes you are looking for in your crop. That’s what the plant produces to protect itself from more UV exposure. Just like us, plants create their own natural sunblock.

The main advantage of IR light is increased PAR thanks to the Emerson Effect. With high photosynthesis rates, more energy is given to the plant to grow bigger and stronger. plants getting IR light will begin to grow outward because of the shade avoidance response. That's an advantage for cannabis plants as they have more surface area to catch more PAR.

The Cons of UV and IR

Too much of both UV-A and UV-B can suppress photosynthesis, making the plant much less efficient at growing. Not only that, but UV light can damage crops physically. UV light can damage the DNA of plant cells, causing them to die, which affects the plant's appearance and growth.

Too much IR radiation can also be an issue because to plant the majority of IR radiation is felt as heat. Too much heat can stress out your plant and ruin your crop. Furthermore, because of the shade avoidance response, the stretching of the leaves and stems may be too much. When growing cannabis plants, we want vigorous, healthy plants that can sustain the weight of massive flowers.

So the plants don't need UV & IR all the time. As UV and IR are only beneficial under the right circumstances. That’s why professional growers will use separate UV and IR light bars to accurately control their lighting and get the real benefits of UV and IR.

If you’re really interested in the benefits of UV and IR, you’re better off getting supplemental UV and IR light bars to add to your grow room. A full-spectrum LED together with supplemental UV or IR bars will contribute a lot to your grow.



Mars Hydro has no UV or IR bars at the moment. What we have are LEDs with a dedicated spectrum to support various grow cultivation applications.

LEDs with the right ratio of IR and red light: TS series

LEDs with a small amount of UV and IR to mimic sunlight: FC-3000, FC-E 3000; FC-4800, FC-E 4800.

LEDs without UV or IR high red light: SP3000, SP6500.

LEDs without UV or IR warm white light for precise control: FC6500, FC-E 6500.


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