The Dude Grows Show

UV Lights and Terpene Levels

I recently added on an HLG 30 UV-A light to my HLG Scorpion and was wondering if others are seeing noticeable improvements on the terpene levels of their flower when using UV light? I see that some preliminary indications are showing up to a 30% increase in terpene levels.



15 responses to “UV Lights and Terpene Levels”

  1. CookingWithCoco Avatar

    I have a similar uva add on on my mars fce 6500. I didn’t notice any difference with uva in terms of taste, effects, or visual trichome production. I don’t have any testing though so there may be some negligible increase that lab equipment can notice. UVB for sure does something ain’t seen no bud frostier than buds grown under a 3100k cmh bulb(will try supplementing uv flouros sometime in the near future though, the white papers on the solacures look promising. I know some folks use reptisun bulbs too and they’re significantly cheaper for the same tech(horticulture companies trying to recoup that r&d money increasing the cost of already available tech)

  2. RamblinFarmer Avatar

    I use the same uv-a light. I bought it between under the center of an Electric SkyV3 in a 2×4 as a finishing tent and also I move it around the outside perimeter of a Ilogic9 which is in a floor space 8×6. An hour each side. Though I forget and it gets extra time some sides.
    What I’ve gathered from adding the light to a total of 19 plants, dried and smoked on is flavor is absolutely greater, smells are stronger. Without a doubt. I am understanding the balancing act of exposure. Though I haven’t seen any negative effects from over exposure, I think when exposed the plants focus is extra protection from uv a/b and not in full stride for flower production. So in a sense I’ve told myself I’m ok sacrificing any miniscule weight for the added smoking experience. I’m growing for me, so it’s all about experience and effect.
    One thing I can say is one key variable to using the light is lower humidity and temperature at night. It really doubles down the desired affect you are wanting out of the light.
    Happy Growing

  3. RamblinFarmer Avatar

    I can also say I believe with the added terpene level (can only assume a higher cannabanoid level as well, not lab tested) the buds are also denser from the added uv-a/b. The plants love it. If they weren’t praying before the uv goes on, they are by the time I turn it off.
    Makes me wonder how much it is really a defense reaction they have and not just a accelerated metabolic reaction increasing oil production.
    Eh….. Who knows

    The only way we really know the true affect on what we do during the grow is to have an optimal finish blue print example to judge how our finished crop
    compares to.
    But I can say that light is a plus to my garden. Actually buying a second one, it’s that much of a difference maker to the finished product.
    I won’t have to move around the one I have from grow to grow.

  4. New Leaf Avatar

    I’ve been using UV-A for the past 3 or 4 runs in my 4×4. I pretty much run it all the way through flower. I run it the entire lights on cycle, minus the time i have reserved for sunrise and sunset. I’ve also introduced it during late veg for like 4 hours of the light cycle. I can’t say I’ve noticed more terpene production. I haven’t run side by sides with clones though. But the one thing I kind of notice is more color. Could just be the strains. Hard to say.

  5. Mike Avatar

    Appreciate all the responses! I am going to try it a few cycles and see how it goes.

  6. MidMOGrower Avatar

    To me UVA is pretty much useless. You need UVB you will see more production out of your buds in Trichromes and Terpines. I have proven this in my side to side grows(test done twice). The one without was frosty but not as much as the UVB(I did not do any scientific testing just use my eyes, my nose and taste). As for turpines it was a huge notice of flavor, definitely the UVB had a lot more depth of flavor. I have need using UVB from Migro since 2019 and it’s been a good investment. Happy growing DGC.

    1. New Leaf Avatar

      How long do you run the UV-B in a single day?

      1. Mike Avatar

        HLG says to run it 12hrs during the flowering cycle. I started at 1 hour per 12hr cycle and have added an hour each day. I`m up to 6 hrs per 12hr light cycle now and the plants seem to really like it. I also found a great utube vid today by Dr. Bruce Bugbee from Utah State University titled “How Ultraviolet Light Affects Plants with Dr. Bruce Bugbee”. I learned a ton about UV light from an 11 minute vid – highly recommend it for growers.

        1. Mike Avatar

          I will probably do like you on my next run and add the UV light during the veg stage as well as flower.

          1. MidMOGrower Avatar

            UVB use only in Final weeks of flowering not in veg.

      2. MidMOGrower Avatar

        I do 2 hrs on for 2 weeks. Some ppl do 1 hr on 30 mins off and 1 hr on again.

  7. Mike Avatar

    I found a really interesting utube video today from Dr. Bruce Bugbee at Utah State University titled “How Ultraviolet Radiation Affects Plants…” My take from it is that UV-A at the 350 to 400 range are good for plants and that you do not have to worry nearly as much about burning the plants as with the UV-B range of light.

  8. Mike Avatar

    Thanks DGC for covering this topic in yesterday`s grow talk episode with a really knowledgeable panel of professionals!

  9. Mike Avatar

    Hello DGC! Thanks again for covering the UV topic. I am seeing a lot of different discussions on which type of UV to use. HLG and Black Dog LED companies only make UV-A lights at this time for specific reasons. If there is any way possible, could you guys get an expert on UV from HLG to come in and further discuss this important topic? I am fascinated by this, and The Dude is so right, we are trying to mimic the sun.
    Thanks again guys!

  10. BarelyBurningBurleyBurnHardt Avatar

    I have a uv 20 w qb18 but I have been running it all the time with my lights prolly burned mine with it.

Leave a Reply

Recent Posts

Dude Grows Show 2024 DGC Cup Preview


Dude Grows Show 1643

What’s Growing On DGC? The Dude and Scotty are Hanging Out Talking Cannabis News, Culture and Growing. THIS…

Roots Organic

I’ve been using Roots Organic either OG, 707 soil (or if available for flower transplant Lush) and I usually…