The Effects of UV light on Cannabis Production and Potency

MH bulbs do not produce any UVA/UVB spectrum. Only HPS bulbs do. Even my 1000w HPS dual archs don't produce enough to show an increase. As soon as you put them in a hood with glass between them you loose it all. Plus uva/uvb rays only penetrate a few inches away from the source. The new 10.0 reptisun bulbs are up to 18 inches deep. Thats what I use. I have 12 of them in my room! Im a white boy whos lookin pretty dark now! Everybody thinks Im tanning. Make sure you where I protection.

MH bulbs increase cbd's. HPS increase thc's along with the blue light spectrum and uva/uvb is a killer combo! My HGK is testing 28% and my chem dawg is testing 27%.

I posted a thread on this already if you want to search for it. You can also follow this link to the paper I published on the subject along with a bunch of research I did from other sources.
http://medicalmarijuanagrowing.blogspot.com/2013/02/uvb-uva-lighting-study-results.html

odin92681 said:

The whole LED area is new to all of us and it's important cause it would cut our electricity by $$$ not cents. We just need more data to be proved that if works.

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From what I can tell so far with LED's by experience is the law of conservation of energy stands... Energy input is equal to energy output.

lansingautorepair said:

MH bulbs do not produce any UVA/UVB spectrum. Only HPS bulbs do. Even my 1000w HPS dual archs don't produce enough to show an increase. As soon as you put them in a hood with glass between them you loose it all. Plus uva/uvb rays only penetrate a few inches away from the source. The new 10.0 reptisun bulbs are up to 18 inches deep. Thats what I use. I have 12 of them in my room! Im a white boy whos lookin pretty dark now! Everybody thinks Im tanning. Make sure you where I protection.

MH bulbs increase cbd's. HPS increase thc's along with the blue light spectrum and uva/uvb is a killer combo! My HGK is testing 28% and my chem dawg is testing 27%.

I posted a thread on this already if you want to search for it. You can also follow this link to the paper I published on the subject along with a bunch of research I did from other sources.
http://medicalmarijuanagrowing.blogspot.com/2013/02/uvb-uva-lighting-study-results.html

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Dude can you site any of this? What your saying about MH and HPS bulbs is not accurate according to the graph on the side of My Sunmaster MH and my Horti HPS. And all the B.S. about MH producing CBD? AND HPS producing THC is also B.S. it's all to do with genetics, I site CBD crews Literature. Lord almighty!!

Peace

botanyofdesire said:

I was doing a Google search on something and stumbled upon an old thread here that had some discussion about UV light. Some people were very fast in there belief that UV has no effect on plants, well others, one even said Ed Rosenthol claimed that UV light would increase potency.

For some reason this debate seemed to stop inconclusively. I am new to this forum and apologize if the topic has already been brought back up and I am just unaware of it.

However this is a very interesting topic. So, what are your ideas? Do you have any information regarding the effects of UV light on cannabis growth or potency? Lets get that debate rolling again.

I have found this information (extracted from http://www.cannabisculture.com/articles/2696.html):

A researcher conducted a controlled experiment in a greenhouse. He lit a group of high potency plants similarly except with the addition of UVB light to some groups. He found that the percentage of THC increased in a direct ratio with the increase in UVB light. This research confirms the adage that high altitude plants are more potent than those grown at low altitudes.
If you look at old-world land races of cannabis, plants that have become adapted to the climate and latitude, the ratio of THC to CBD starts at 100 : 1 at the equator. At the 30th parallel (The Hindu-Kush Valley) the plants have a ratio of 50 : 50. At the 45th parallel the ratio is near 1 : 100. This corresponds roughly with the amount of UVB light received at these latitudes. There is much more UVB at the equator than the 45th parallel.
How can you get more UVB light to your plants? Certainly it's true that MH lamps emit more UVB light than HPS lamps. Still the amount that MH lamps emit is small. In fact, many manufacturers use UVB shielding glass to filter out most of the UVB that's produced. The UVB light the plant receives from an MH lamp does increase the plant's potency slightly at the cost of yield, but there are better ways to introduce UVB light into the grow room. They include reptile lights, which emit about 10% UVB, and tanning lamps.
The problem with using these lamps is that they are associated with increased number of cancers and many other problems. They should not be on when you are in the grow room. Not much research has been conducted on using them to produce higher THC values. I will do a full report in a future issue.

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the reason for most of the controversey is most likely due to shady led grow light companies advertising UV. Currently there is no technology allowing to Manufacture UVB leds unless you want half a milliwatt. all the led companies that advertise UV are using UVA which has no benefit to your plants that couldnt be greater acheived with violet and blue wavelengths its a simple marketing ploy. There is one company that using the reptile uvb bulbs along with there leds. BUt even the 10 percent uvb reptile and tannings bulbs are still fairly low in concentration and producing unnecessary heat and wavelengths. To truly see the benefits of uvb narrowband phototherapy lights should be used these are well over five times the concentration of 10 percent uvb bulbs. The bubls are also very dangerous and should never be exposed to ur skin or eyes while on, ( although they are used for treating skin they are only exposing it to their skin very briefly and are still at risk of skin cancer). you need to experiment wwith these lights gradually increasing the exsposure to your plants. its best to go with a higher power then you think you need an limit the exsposure time. some people turn em on briefly every hour. Myself i try to replicate the sun and have a low power reptile one on all day that is raised high above the plants then i have a higher powered phototherapy bulb that turns on in the middle of the day increasing from 15 minutes to two hours by then end of flowering

I have a 2 bulb uvb light for a home heat ducting. I used it to kill off powdermold last year. It draws around .2 amps. How far away from the canopy would you have this. I have a 4x7 grow area with 2 330 LED panels @ 12" to 16" from the canopy. I rotate to the center to finish under both panels (perpetual). I was thinking 15 minutes an hour for 4 to 6 hours. What do you think, to much.