Does UV enhance THC output?

[BunkerMonkey]

Hey A1...UV-B doesn't exist at night and it's also insignificant in the morning and late afternoon. What kind of UV-B bulbs are you running? I have some badass UV lights and I think I was running them a little too close on one plant and a little too long on the other.

They still haven't grown pot that's too potent for me.

Here's a LOT of quality info on UV-B -

UV Lighting for Reptiles: A new problem with high UVB output fluorescent compact lamps and tubes?

 

[A1cronick]

i would disagree with you on that link being good info it might have been 7 years ago when it was written here is some new info using the same bulbs i use from 2013 it also says they have made changes to the uvb bulbs so that would have been a good read 6-7 years ago read this 5 strains increase thc by up to 5% under uvb real study real results Redirect Notice

 

[BunkerMonkey]

Yup, Good ol' Lansing Auto Repair! So far he's done the only REAL science on UV-B and THC. Last week I commented on this post of his. I sure would like to have a conversation with LAR.

UVB UVA Study Test Results Increases Medical Marijuana Potency 3-5%: How to achieve uniform THC and CBD results with the use of UVA UVB lighting.

 

[BunkerMonkey]

And A1...I respectfully disagree with your disagreeing. It's true that ZooMed Reptisun Compact Lamps, Big Apple Herpetological Mystic Lamps and R-Zilla Desert 50 Series lamps have changed since 2007, that's in the first paragraph, and maybe some of the other lamps have changed their phosphors too, but there is still a boatload of good information on that Reptile site relating to the total power output of all the Lizard Lights and how the distance from the lights relates to Solar UV index and other neat shit to know about like reflectors and hoods. Every little bit of knowledge on the subject helps.

Here's the section on reflectors and hoods -

UV Lighting for Reptiles: A new problem with high UVB output fluorescent compact lamps and tubes?

 

[A1cronick]

none the less i believe uv-b has a strong effect on thc and also on turps hps lights and led produce zero uva-uvb so even if the uvb is equal or less than the sun at some distances i still have uvb in my grow where as all other hps or led grows have none i believe this gives my weed a edge that most others dont have

if you think those bulbs are inferior try a arcadia 12% uvb t5ho supposed to be best uvbs around

i also did read that aluminum reflectors increase uvb under the light by double and i do have highly polished aluminum reflectors

i would not discredit the study because of the name it was posted by it clearly is a singe individual growing weed trying to get the most out of his grow

 

[BunkerMonkey]

No way am I discrediting Lansing Auto Repair. The dude took the time to do some real science. I planb on using UV-B in all my grows, even if it does reduce the yield a little as I've read elsewhere. With corporate growers right around the corner my goal is to produce connoisseur bud that they can't touch.

Thanks for the heads up on the Arcadia 12% UVB T5HO.

 

[A1cronick]

i like the way you think quality is 1st and 2nd priority yield is 3nd in my opinion but yea if you use those bulbs there supposed to be 100%legit and if you can get 12% uvb thats some kush valley uvb or top of a mountain shit and thats where all of the best strains in the world come from is those areas do it up make it happen when i got some extra $$$ im buying two of those bulbs and adding them in

 

[Icemud]

i would disagree with you on that link being good info it might have been 7 years ago when it was written here is some new info using the same bulbs i use from 2013 it also says they have made changes to the uvb bulbs so that would have been a good read 6-7 years ago read this 5 strains increase thc by up to 5% under uvb real study real results Redirect Notice

I like the study that you posted and I too believe that UV helps increase the protective responses in plants, thus increasing resin, however, I see some flaws in regards to this study.

The UV reptile bulbs uses are not just UV only, they also contain a very heavy blue profile on the spectoral readouts as well as heavy in the orange/red area. The reason I mention this is that most photosynthetic plants have most of their photosynthetic pigments with peaks in the blue/violet region. These pigments are responsible for helping the plant not only maximise photon efficiency but also adapt to the environment. Since many pigments in the blue/purple region are also responsible for triggering protective responses in the plant, the increase in THC might be contributed to the addition of extra blue spectrums in the grow, and not solely on just UV alone. For a more accurate test with quantifiable results, I would suggest they redo their testing using specific UV LED chips blocking out all other spectral regions. This would isolate the results truely to only UV light.

 

[BunkerMonkey]

Excellent point, Icemud. I remember reading that UV-B reduces crop yield So it follows that the phototropism I see in my plants toward the lizard lights is probably due to the blue spectrum only. I had a 1000W halogen work light in the flowering room for about a week and the plant I had it on showed increased growth and photropism in that direction. Too bad that the majority of a halogen light's spectrum is in the Infra Red. It sure as Hell puts off some heat so it's not in there anymore.
UV-B LEDS with specific 10nm output ranges between 240nm and 355nm can be purchased, but the shorter the wavelength the pricier they are. Isolating the exact wavelength(s) of UV light that increase THC production can be done but it would take a few years and or many thousands of dollars to buy all the LEDs required. The research has probably already been done by a corporation and is stashed away in a vault somewhere.

UVTOP TO39 Flat Window

 

[Conradino23]

Has anyone else noticed speed flowering when forcing outdoor in June or July. My temps are around 97°F in the shadow now, and my plants have not only started throwing off ridiculous amounts of resin, but also turning pistils' color... on 11th day of flowering. Cotton Candy, which is supposed to be a 9weeker looks like is gonna be ready in 6 or 7 tops. I do not have any doubts it's due to UVB on max level, but I'm looking for more testimonies.

 

[Stress Relief]

Wow two UVB threads on this forum Glad to see people are catching on that you don't need always flower under a yellow light.

 

[Conradino23]

I got sth for you UVBers here.
It's been verified!!!

Lydon, J., Teramura, A. H. and Coffman, C. B. (1987), UV-B RADIATION EFFECTS ON PHOTOSYNTHESIS, GROWTH and CANNABINOID PRODUCTION OF TWO Cannabis sativa CHEMOTYPES. Photochemistry and Photobiology, 46: 201–206. doi: 10.1111/j.1751-1097.1987.tb04757.x

Abstract

The effects of UV-B radiation on photosynthesis, growth and cannabinoid production of two greenhouse-grown C. sativa chemotypes (drug and fiber) were assessed. Terminal meristems of vegetative and reproductive tissues were irradiated for 40 days at a daily dose of 0, 6.7 or 13.4 kJ m-2 biologically effective UV-B radiation. Infrared gas analysis was used to measure the physiological response of mature leaves, whereas gas-liquid chromatography was used to determine the concentration of cannabinoids in leaf and floral tissue.

There were no significant physiological or morphological differences among UV-B treatments in either drug- or fiber-type plants. The concentration of Δ9-tetrahydrocannabinol (Δ9-THC), but not of other cannabinoids, in both leaf and floral tissues increased with UV-B dose in drug-type plants. None of the cannabinoids in fiber-type plants were affected by UV-B radiation.

The increased levels of Δ9-THC in leaves after irradiation may account for the physiological and morphological tolerance to UV-B radiation in the drug-type plants. However, fiber plants showed no comparable change in the level of cannabidiol (a cannabinoid with UV-B absorptive characteristics similar to Δ9 THC). Thus the contribution of cannabinoids as selective UV-B filters in C. sativa is equivocal.

 

[Sonisk]

So, adding UVB will increase THC levels?
I gotta look into this I think.

 

[SGL D]

Awesome discussion. We have been testing adding Far Red ir spike at 730 nm and adding uv spike at 470 nm in tests and getting good results. One of the strengths of induction during Veg is the IR and UV IMO

Too much is not healthy from what I have been told when it comes to potency. Plants naturally put up a sunscreen to fight off excess UV and IR light and cannabis shown to have thicker trichome walls and end up holding less THC or CBD and decreases potency. Not sure on the effects of yields, yet.

 

[BunkerMonkey]

Great link, Conradino23! I haven't had any lab testing done, but the plant that I exposed to UV-B for the last 30 days of flowering is definitely more potent than it's sisters.

 

[OttawaGreen]

Is everyone else finding the uvb plants seem to be maturing faster?

 

[cannacrazy]

Hey man, you in the UP? I'm using 4 reptisun UVB (30%) UV (10%) in a sun blaze 4' T-5 fixture. On 10 minutes off 15 every flowering hour last 2 weeks. It's supposed to increase THC levels by 5% or more. I always get more potent buds with the combination of HPS, MH and the reptisun high output UVB lights.

 

[BunkerMonkey]

Dudes, at first this guy said the plants needed to be exposed to UVB in veg and flower. Now this more recent blog of his says that the UVB is only needed during the last phase of flowering. This would reduce damage caused by the UV light to growing plant structures.

UVB UVA Study Test Results Increases Medical Marijuana Potency 3-5%

 

[BunkerMonkey]

I dried,cured, and stored these budz separately from it's sister plants in an RDWC system. Even though I didn't get it lab tested, I can report that the field testers prefer smoking this plant to the other plants. Hands down.

 

[Conradino23]

Is everyone else finding the uvb plants seem to be maturing faster?

Yes, I do and was wondering the same.