Variable-spectrum LED lights present growers with the opportunity to have control over their plants, tailoring everything from smell to taste to potency. We have talked before about how different spectrums affect plant growth, but the issue of UVB light for plants is still somewhat controversial. Ultraviolet light can be dangerous, so growers often struggle with the issue of whether to use the UVB light spectrum at all.
Historically, the plants with the highest THC levels have grown in higher altitudes or near the equator, which naturally get more UVB light. Through careful experimentation over the years, many growers have realized supplemental UVB lighting can create more potent plants. However, using the right amount is a delicate balance.
Below, we will go over how to safely and efficiently use UVB light for plants to create an amazing final yield.
How Does It Affect plants?
Invisible to the naked eye, ultraviolet light is a type of electromagnetic radiation that is usually completely absorbed by the stratosphere before it even reaches Earth’s surface. It is the shortest wavelength in the spectrum. While harmful in large amounts, UVB light does have benefits – particularly for plants grown indoors, which are not exposed to UVB light naturally. Most all indoor lights filter out UVB to avoid human exposure.
The mechanisms in which UVB light affect plant growth are complicated and still not entirely understood. Research is ongoing, but scientists have identified a few key ways in which UVB light affects plants.
One reason UVB light can be damaging is because plants contain a protein molecule called UVR8. UVR8 is made up of two protein subunits, which break apart when exposed to UV light. This triggers a number of changes in your plant’s subatomic structure, many of which can be harmful. However, there are also some potentially beneficial results of the breakdown of UVR8.
One such change is the stimulation of the chemicals malonyl-CoA and phenylalanine, which sets off a chain reaction that can actually help your plants. Plants use malonyl-CoA to make Olivtol, which they then use to make THC. As you can see, small, strategic exposure to UVB light can increase THC level. This means, with the right amounts at the right time, you can create an incredibly potent final yield with the help of UVB lighting.
Obviously, taking advantage of UVB lights is a delicate art. It is all too easy to cross the threshold into damaging your plants, especially if you’re new to growing. It should be used with extreme caution.
How Do I Use UVB Light For Plants?
UVB lighting – when used correctly – can have a powerful effect on your final yield. Maryland researchers found that plants exposed to UVB radiation produced almost 28% more THC than plants grown without intentional UVB exposure. When plants grow under UVB in proper conditions, the results can be dramatic.
In this particular study, growers used UVB-generating sun lamps throughout the grow cycle that were placed 10 inches from the canopy. This provided small amounts of UVB exposure.
However, the bulbs used in this study are not readily available to the typical grower. While you can purchase UVB-generating lights made for housing reptiles like lizards at pet stores or for indoor tanning lights, these are not recommended for growing plants as they are underpowered and less effective.
The absolute best means to take advantage of UVB lights is to use lighting specifically designed to appropriately regulate UVB exposure. This is why California Lightworks sells specially designed fixtures with integrated supplemental UVB lighting, specifically designed to stimulate THC production without damaging your plants.
Some growers use UVB in small doses throughout the grow cycle, while others increase UVB during the flowering stage only. Different strains will respond differently to any light on the spectrum, so it may take some trial and error to figure out what amount of UVB lighting is right for your plants.
Most growers who use UVB light to increase potency expose flowering plants to moderate levels of UVB during the last two to three weeks of bloom when flower and resin development is present. Different strains will react differently, so some experimentation is required. Too much UVB will quickly damage plants so it is always recommended to start with lower doses. Many growers have ruined an entire crop due to excessive UVB exposure.
And most importantly – UVB can damage skin and eyes. Never work under a UVB light! Follow all instructions carefully.
UVB Light For Plants: The Bottom Line
There is still a lot to learn about the effects of UVB lighting on plant growth, but research has definitively shown that – when used at responsible levels – it can greatly increase potency. It can be difficult to regulate UVB light with products like lizard lighting of tanning lights, so lights specifically designed to regulate UVB lighting for plants are the best route if you want to take advantage of ultraviolet light during your own grow cycle.
While it may take some experimenting, UVB lighting can help you customize your yield and create a more potent final product.
ALWAYS USE CAUTION WHEN USING UVB LIGHT – HUMAN EXPOSURE CAN DAMAGE THE EYES AND SKIN. NEVER WORK UNDER UVB LIGHTING AND FOLLOW ALL INSTRUCTIONS!