Lighting Ultraviolet and THC

[armanidog]

I was reading this article:
"Grow Hack: Does UV Light Increase Cannabis Potency?"
http://www.hightimes.com/read/grow-hack-does-uv-light-increase-cannabis-potency

I searched for UV and ultraviolet on the forum but did not find a thread discussing this.

Ultraviolet radiation in all forms can be damaging, but UVB rays specifically damage proteins and nucleic acids in the cells harming processes of cell reproduction and metabolism. The energetic, short wavelengths rays of UVB radiation pack the punch, and are largely responsible for sunburn and play a major role in skin cancer.
To defend against UVB, some plants produce flavonoids that can absorb the radiation. In humans, exposure stimulates the production of melanin to defend against the sun.
Evidence shows that cannabinoids, specifically THC, may play an active role in defending the cannabis plant against UVB rays, and strains native to areas with high levels of ambient UVB radiation show higher levels of Δ 9THC.

They linked to this scientific article:
"UV-B RADIATION EECTS ON PHOTOSYNTHESIS, GROWTH and CANNABINOID PRODUCTION OF TWO Cannabis sativa CHEMOTYPES"

http://onlinelibrary.wiley.com/doi/10.1111/j.1751-1097.1987.tb04757.x/abstract (You have to pay to get the whole article, I have not paid to read the whole thing).
The 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[SUP]-2[/SUP] 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 Δ[SUP]9[/SUP]-tetrahydrocannabinol (Δ[SUP]9[/SUP]-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 Δ[SUP]9[/SUP]-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 Δ[SUP]9[/SUP] THC). Thus the contribution of cannabinoids as selective UV-B filters in C. sativa is equivocal.

I will wait until he writes about how much UV to give a grow and other specifics before I think about trying it.
Anyone have experience with using UV lights periodically during a grow?

 

[Corgy]

This is a very interesting subject, strange timing as I have been looking into this the last few days after I came across the Cleanlight mould eradicator in an online growshop

http://www.cleanlightdirect.com/en/cleanlight-home-garden.html and yes, they are used industrially....

But that is UVC, not UVB, so still looking into it.... That is, can this light thingamajig be used without HARMING a cannabis plant and it's contents.... I digress

I did come across MANY references to the benefits of UVB like the one mentioned above, will post some links later when I'm home and off the mobile.

For starters here is Ed Rosenthal saying UVB is beneficial and increase the THC content

http://mjgrowers.com/book_what_exper1.htm

UVB LIGHT

Ultra-violet B light is a spectrum of light that is invisible to us but is visible to insects and some other organisms. In humans it causes suntan and sunburn and is implicated in the formation of eye cataracts. It is the light emitted by tanning bulbs.

UVB light also affects marijuana potency. The potency of high quality marijuana increases in direct ratio to the amount of UVB light it receives. This is very significant. In California, where the medical dispensaries operate in an unrestricted market; many dispensaries reject fall harvested outdoor material as inferior. They have found it lacks the potency of indoor crops and is a harsh smoke. However, when they were presented with marijuana grown outdoors but forced to ripen August 10, they accepted it as if it were indoor because of its high potency and lack of harshness. I think the harshness results from cool nights.

Indoors, under fluorescent and HPS lamps, gardens receive little UV-B light. Metal halides emit a bit more. However, there are ways of supplying your garden with UV-B light. Tanning lamps work, that is, lamps that tan people, because of the UV-B light they emit. Using tanning lamps will increase the THC content of the crop. Reptiles and lizards require the spectrum to stay healthy. So the spectrum usually comprises about 10 percent of their output. If you want to try tanning lamps they are available on the Internet. Use between 5-10 percent of your total wattage to these lamps. For a 1000-watt garden use 100 watts of special lighting.

Adding UV-B light to your garden will enhance your marijuana naturally, without “special formulas” and chemicals.

 

[growbiewon]

Anything that helps bring indoor environment closer to the big halide in the sky is good in my book.

Generally these are in the form of cfls reptile lights.

Although I've seen a large grower use t5 uvb lights bracketed to his air cooled hoods running two per light with 4 to 8kw if I remember correctly.

When asked frequently if they really worked , the grower always replied, I wouldn't waste the money or my time attaching these to my hoods it if it didn't work...

I have never used them but I would love to possibly try a 12 bulb t5 auto tent with a few uvb mixed in.

 

[paddler54]

Okay I have 4 24 inch t5 fixtures loaded with arcadia 10.0 I believe bulbs. They are uvb and I plan on tunning them for 5 hours a day. Distance will be factored in when I start my grow. Finally moved got both tents up but I am waiting on procuring ph up down which I have to go off island for. And I still need to test my modified dwc design before I commit my embryos to the rockwool. We shall see.

 

[paddler54]

These are the light I was talking about. Arcadia D3 24 watt 12% uvb. Don't get the reptisun t5 bulbs they are not strong enough. Unless you are a reptile, please do not expose yourself to the light from these beauties. They were $30.99 apiece. You can get them online at www.lightyourreptiles.com .

 

[81camaro]

This is maybe a subject worth more input. It's my impression that the equatorial strains benefit from increased UV light spectrum which increases potency. I recently upgraded to an LEC 315 ceramic metal halide. Based partly on open hood. Glass apparently filters out much of the UV band. I'm soil and organic as possible, 5 gal airpots x 2, 3x3 scrog. 3 month veg. pistils showed on April Fools. lights been up a few days, and so far so good. Quality, not quantity, is my main goal. I know the LEC spectrum is high in UV generally, but mainly UVA. I may be hanging a few of these reptile bulbs myself to increase UVB. Good info, Thanks dude!

 

[81camaro]

Hey Corgy. Plants lack the machinery for UVC I think or it's insignificant. I;m looking into the UVB though. I'd like to get a 24watt T5 over each plant. I'm settling in on the pair over the 3x3 as enough light at 12-15 inches from canopy. Still a $100 away, working on it, lol, the reptisun 10.0 aren't the best, but good enough. You can have too much. Looked at a megaray brand tube today that seems pretty sweet though.

 

[Corgy]

Yeah, UVC is bad news, reason why it's used in sterilizing thingies, and it's not present in the outdoors being completely blocked by the ozone layer......at least so far.....!

I asked 2 LED sellers why they don't use UV in their lights, both hasn't replied so far, one even claimed UV LED's don't exist.....!!!!

I think there's no real solid scientific evidence to whitelist UVB and THC as brothers in arms..... Conversely there is no solid evidence they are NOT.....

Suffice to say many growers manage to produce copious amounts of THC without giving UV a second thought ..... So as the sticks are standing for now, it's a matter of personal preference and curiosity in possible industrious refinement......

I suffer from the annoying Persistent Curiosity Syndrome (known as PCS amongst those grossed out by this irritating and itchy disease),...... So yeah, I'll give it a play too...... As said above, mimicking the outside radiation as closely as possible seems worth a go.

Don't forget to bring your 100 % UV blocking spectacles along on your quest..... Possibly a beach chair too for a nice suntan while basking among lush weedy vegetation.....