Does UV enhance THC output?

A

Alpha

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I have a friend who grows a lot and I think is credible advise me to add a UV light to my grow room when flowering. He said that it encourages the plant to produce lots more resin which in turn creates THC, he actually said that it virtually doubles the THC output of the plant! Obviously if this is something well worth doing if true, but all the searches that I have dome online really don't tell me much... A few brief discussions around, but most people getting confused and talking about growing 100% under UV.

If this is a technique that works, I'd like to know what type of UV lights, bulbs I should be considering, eg UVB etc... What power, what stage to apply, for what time duration and so on... In my mind it makes a lot of sense that this would work...

Thoughts people please!
 
Re: Does UV enhance THC output??

There is research that shows UV light does increase the plants protective defenses, increase beta carotene, oils, and resins. You probably know by now that there is very little research done on cannabis other than what is done in communities like this one. With all of that being said, yes UV light should increase THC as it is a resin produced as a defense mechanism. Can I give you 100% guaranteed proof? No, sorry I can not.

If you are going to add UV light, make sure that is a small amount because too much will kill your plants. The UV you are looking for is NUV or near UV between 365-380nm. Florescent lamps, black lights, and most LED's will fall into this range most of the time.

Remember that UV light is bad for you... Too much UV light will cause skin cancer and can hurt your eyes. Don't look into it.
 
I grow outdoors in the summer at 4000 feet in the mountains. Our UV INDEX highs during the summer can hit as high as 12 or 13 on a the EPA Scale of 0 to 15!

The plants do fine in with it in veg, and my recent finishing of flowering plants outdoors does seem to substantiate this claim. Just harvested some Blueberry Kush that spent the last two weeks finishing in the intense Sierra sun with IMPRESSIVE results!

Sent from my iPod touch using Forum Runner
 
Re: Does UV enhance THC output??

Those reptile UV bulbs + fixture will work. Have them on a different timer and turn on for less hours than the lights you're using in bloom, however it has the same off hours. Too much is not good for the plants nor too close. Start them after 4th week of bloom to give time for the plants to mature enough to withstand the UV bath.
 
Re: Does UV enhance THC output??

Some great feedback there people, any advice on the power of the bulbs? I'm currently thinking about getting this and screwing it into a spare 400w ballast I have, but I am worried that it could be a little OTT.. Also, when I switch to 12/12, how long would you have it on for? Distance from plants etc etc..

Chursssssss
 
Re: Does UV enhance THC output??

I would personally do it at all times you have lights on, the sun gives off UV light at all times. Waiting until 12/12 may cause more stress due to the fact that the plant is not used to it. The 400W bulb seems like it is a bit much you you didn't tell us how large of an area it will be covering. I wouldn't go much above the 4% of total light output that you currently have. Here is a report that covers light output by lamps and the Sun.
 
Re: Does UV enhance THC output??

I know that towards the end of, and after harvest, High levels of UV light can cause the THC to degrade at a faster rate than normal, to be safe id stop using the UV altogether for the last 2-3 weeks of flower. Other than that id really like to see your results,
All the best.
GA
 
My main tent is about 1.2m wide and long and 2m high.. Looking at a lot of lightsnand really unsure about what type, strength etc I should use. Btw thank you all for your responses, defo moving in the right direction!
 
You guys might want to take it slow with the UV, since I am starting to see some pretty convincing evidence that too much UV can definitely SPEED THC degradation to CBD and CBN. If you want to speed up maturation, then this looks like a good way to do it, but I would proceed with caution and definitely use a microscope!

More details on my outdoor flowering experiments this year...

I've been finishing some 6-7 week indoor flowering GDP and Blueberry Kush outdoors, and they seem to definitely be maturing much faster than I have seen under artificial light. As I previously mentioned, I am at about 4000 feet in the Sierra Nevada and I also have a weather station run by the National Weather Service nearby with a UV sensor on it. Our High UV Index levels over the last three months has been averaging about 9.5 which on the EPA scale of 0 to 15 is considered VERY HIGH. We have had a few days back in June and July where we were hitting 12s and 13s for highs with is EXTREME! A few of these plants were out there in that in July.

This is the first season that I have attempted to finish flowering anything outside in the sunlight. Was primarily forced to in the beginning due to indoor space constraints with my flower room's capacity.

Anyway... I am about to post some trichome images in my GDP thread that are showing a significant amount of amber trichs at Week 7.5. This is the Genuine GDP strain and it usually finishes at 8-10 weeks, so this plant is way early!

Only thing I can think of is the UV factor. I am seeing purple pigment in many of the Trichome stalks, so I am going to buck my usual rule and let it keep going to see if I get the color change. If this were any other strain I would be chopping it today!
 
Goldengoose7 said:
You guys might want to take it slow with the UV, since I am starting to see some pretty convincing evidence that too much UV can definitely SPEED THC degradation to CBD and CBN. If you want to speed up maturation, then this looks like a good way to do it, but I would proceed with caution and definitely use a microscope!
Click to expand...

Thats what i thought mate, but the question now is whether it speeds up bud growth aswel. I suppose its not so much a fair test with an outdoor grow seeing as expected yield is probs higher anyway and there are so many determining factors. I dont usually do the same strain twice but i may have to in order to properly test this out with a control group.
 
Just curious but has anyone ever used aquarium Metal Halides for late flowering/ripening period? I found that they run in 10k, 15k and 20K, with very high blue, red and UV output... Seems like a worthy buy... anyone ever used them?
 
im thinking adding some uvb on top of your main lighting does work this is my 1st grow i have read many of these forums on increasing thc with uvb so i went and put two t5ho 4 lamp 4 foot fixtures each containing one reptisun 10.0 t5 uvb bulb two bloom bulbs and one grow bulb in my flower tent and this pic was about 24-28 days into flower and look for yourself its a current project so i cant say for end results but i can give every one some good input around april 420 with more pics and shit

20140303_092419.jpg
 
Hello A1cronick? Are you still growing? I'm into a UV-B experiment too. I'm on day 30 of flower and day 10 of the UV-B test and it seems to be that the test clone plant is putting on more bud and maturing faster (judging by how quickly the fan leaves are yellowing) than the 2 control cloned plants. Trichome number and appearance seems the same under UV-B as it is under the 1000w HPS. I will be having test and control plants analyzed for THC/CBD/CBC/mold at Iron Labs here in Michigan.
I'm running 2 Reptisun10 2' tubes on the test plant. I also have 4 Reptisun10 CFLs on my favorite strain but I don't have a control plant so there's no science there, just hopes of a higher THC level.
Epiphany_Bud_Day_25_flowering.jpg
 
hello i have been away from the forum for awhile but yes i did add uvb to my grow right after i said i would in my 10x5 tent really 5x5 because im only using half i have the mars II 1200 and 8 t5ho 6 in bloom spec 2 bulbs are the reptisun 10.0 t5ho hers the last pic i took of my set up
20140313_081527.jpg


nug shots of those same plants
20140419_144130.jpg
20140413_103412.jpg
20140413_103403.jpg
20140413_104055.jpg
 
Damn nice buds A1. So did you have the UV lights on for the entire photoperiod? I was running my UV lights the entire 12 hours but a lot closer than you ran yours and it looks like the leaves were getting "bleached" so I backed the timer off to 2 hours per day and I'll increase it if I see some improvement.
 
Well Not sure on UV on this but I will share what I know for sure. When the relative humidity in the garden is low your resin production will increase. This is a natural response cannabis has to dry air and attempt to protect itself from hot dry conditions. Marijuana resin actually has one of the highest UV-resistance ratings in the plant kingdom. The resin reflects light preventing the buds from getting sunburn.Lowering the humidity in the room on that last night before harvest morning will ensure increased resin production without having to let the soil go bone-dry first. Another thing is to prolonged dark periods of up to 24 hours just before cutting can make spikes in resin production. This is all do to low humidity will cut down on light uptake anyway plus it helps to make sure liquid foods within the plants drain down to the root zone. I do not know if that is off topic but that's my take on that.
 

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