What is the best UV light for plants? 2021 Updated

UVA light has been shown to increase secondary metabolite activity in many plants, and this is also the case with cannabis. The most important secondary metabolites from a cannabis grower’s perspective are cannabinoids such as THC and CBD, as well as terpenes which give cannabis its distinctive aroma. Short wavelength irradiation, such as UVA and blue light, trigger the plant’s stress response system and the plant starts to protect itself from the abiotic stress i.e. short wavelength irradiation.

UV Light For Growing Marijuana

Ultraviolet light causes the production of resin, and with it THC and CBD, in order to protect the marijuana plant from harmful UV rays. Thus, adding best UV light for plants to LED grow lights results in an increase in THC in the resulting buds.

There is no question that at its core, UV light is harmful to plants. But in harming plants, it actually causes them to develop protective mechanisms that make them stronger going forward.

With weed, this results in an increase in THC and CBD. For this reason, feeding your marijuana plants low levels of supplemental UV light will actually help them and generally result in better crops, as is the case with cannabis.

For years, tetrahydrocannabinol (THC) got all the attention. While THC certainly delivers its own benefits (such as relaxation and pain relief), there’s a whole host of other — and often overlooked — compounds found in cannabis with important benefits as well. THC is truly only the tip of the iceberg when it comes to cannabis’s potential.

As the cannabis industry evolves with changing consumer tastes and developing medical research, growers may employ techniques to boost cannabinoid and terpene profiles in their harvests — beyond merely focusing on THC. Advanced LEDs allow growers to elicit specific biological responses in cannabis crops, including increased concentrations of these naturally occurring chemical compounds.

ECO Farm 30W LG UV395nm Supplemental Lighting Quantum Board

  • Comes with an easy to use remote control
  • Manufactured here in the USA
  • Designed with 7 different preset times from 5 to 60 minutes
  • Easy to understand digital display for status and run time indication
  • Dual motion sensors for extra safety

Gavita 30W UV LED Grow Light

  • More affordable than most UVC lights for disinfection
  • Made by a very well-known brand in the UV light industry
  • This device has been used to destroy and kill pathogens in rooms
  • Can be used in homes, facilities, offices, schools, and more
  • The powerful UV-C rays target microorganisms that cause problems for people

The Foundation of Cannabis’s Effects

Whether used medicinally or otherwise, cannabis has changed our society and many of our lives — and there’s a collection of naturally occurring chemical compounds, known as cannabinoids and terpenes, to thank.

  • The cannabinoids THC and CBD are the most common and well-researched, however they are accompanied by more than 200 additional compounds, including cannabinol (CBN), cannabigerol (CBG) and tetrahydrocannabivarin (THCV), among others.
  • The cannabis plant also contains terpenes. These structures are responsible for giving flowers (including cannabis), fruits and spices their distinctive flavors and aromas. Common terpenes include limonene, linalool, pinene and myrcene.

Both cannabinoids and terpenes are found in the cannabis plant’s glandular structures known as trichomes. Look closely, and you’ll notice trichomes coating the cannabis flowers and leaves, giving the plant an almost frosty appearance.

Trichomes — which are found across several plant species — are a key aspect of a cannabis plant’s survival. The specific combination of metabolites produced by trichomes may attract certain pollinators and repel plant-eating animals. Moreover, trichomes (and specifically THC) may act as the plant’s form of sunscreen and shield the plant from harmful ultraviolet rays.

While they play an essential part in the cannabis plant’s lifecycle, trichomes are volatile and easily influenced by a range of environmental factors, including light, heat, physical agitation and time. Therefore, environment is a defining variable in the development of these important structures.

Cannabis Sunscreen = THC ?

Because studies suggest that UV light exposure enhances some oil and phenolic compound production, could cannabis plants exposed to UV light create higher THC potency as the result of a protective reaction? The data certainly looks that way, but this hypothesis is not supported by academic studies yet, since it is still federally illegal.

Typical indoor grow lights used in most cannabis cultivation (HPS and LED lights) contain virtually no UV light. But as the industry evolves, expect to see that change. Cannabis production is continuously pushing innovation in technology, and grow lights are no exception. If ultraviolet radiation can be harnessed to increase THC potency and terpenes, the sky really is the limit in lighting and growing technology.

Do Plants Need UV Light?

No, plants do not need UV light. It actually causes them harm. But in causing harm, it forces plants to protect themselves, which can result in a positive for our needs.

Cannabis is the best example. UV light forces it to create more resin to protect itself, which means higher THC and CBD levels. For that reason, many marijuana growers look to add UV light to the final few weeks of the grow, when it has the most effect on the final product.

But what is the best way to give your plants ultraviolet light?

How To Provide UVA/UVB Lights For Plants?

A lot of LED grow lights have UV diodes these days, but they only have UV-A light. That’s because UV-B LED diodes are incredibly expensive and are only included on very high priced fixtures.

There is a prevalent belief that only UV-B light is beneficial to THC and CBD production, but this is based on a poorly run study that did not, in fact, prove this. Black Dog LED did their own research and found that UV-A light also increases production of THC and CBD.

For that reason, any LED grow light that has UV diodes will work just fine to give your plants some UV light.

Nevertheless, I know some people will insist their plants need UV-B light. But using LEDs is not the way to do it.

What is the best UV spectrum for growing cannabis? When it comes to the full UV light spectrum, its best to stick with UV-A and UV-B varieties for your plants. As mentioned, there is no benefit of direct UV-C exposure to yourself or to your crop (although UV-C may help sterilize your grow room). If you are considering using the UV-C technique to disinfect your workspace, consider safer organic alternatives to pest control, including as integrated pest management (IPM) techniques.

Final thoughts

Depending on the species of plant you intend to grow, there will also be a precise formula for just how much UV light you’ll need, and when you should introduce it. In some cases, UV light over prolonged periods has stunted growth. In other cases, it can enhance valuable characteristics of your crop. For example, for growing cannabis, you’ll only want to introduce UV light during the final few weeks of flower, to boost trichome development, but constant UV lighting for leafy greens tends to stunt their development.

But what about grow lights? Do artificial lights include the UV spectrum, and if so will these artificial lights help your plants grow? Modern metal halide and ceramic metal halide bulbs should all produce a low, but measurable UV spectrum of light, but so do many LEDs. So long as you are investing in modern grow light technology, the UV should be built right in. Importantly, reputable grow lights won’t emit any dangerous UV-C wavelengths. ECO Farm Supplemental Grow Light deserves for your try.