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I've been pretty intrigued by this theory. Apparently UV light in the early stages of flowering encourages heavy, and early, trichrome formation. I've seen a few side by side grows and the results are pretty interesting. There is definitely a difference between using a UV and not. However there isn't too much info on using UV light in flowering, i do know it's detrimental to your grow when drying your buds. Also UV light is nasty stuff to work around, you need to turn the lights off when working in the room and you can't look directly at them (unless you want to go blind).
A big upside to this theory is that the lights are cheap and easily found at pet stores and online. Also they don't require massive amounts of power to run so your electricity bill is not really affected by running them. They're also small and versatile so you can fit them in a lot of spaces if your grow room is getting cramped. Once i get setup in my new place i'll be adding one or two of these lights to my setup to see how well they perform.
Also, FYI, MH lights put out some UV rays so if you have a MH ballast and bulb you can achieve similar results by running it alongside your HPS.
I believe that trichome production is a form of self-preservation by the plant against UV radiation. Think natural sunblock. There are many, many papers out there supporting this.
Thus it would make sense that UV bulbs, alongside regular grow lights, would increase trichome production. I wonder how a combination of UVB and UVA bulbs would do. I belive you can buy blacklight bulbs that emit mostly in either region: UVB= 290-320nm, UVA= 320-400nm, visible light= 400-700nm, and infrared= >700nm. I definitely wouldn't want to be around the UVB lights when they're on though. That's the stuff you put sunscreen on for.
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I don't know about the blacklight theory, haven't really seen anyone use one.
Quote: I definitely wouldn't want to be around the UVB lights when they're on though.
Yah, i already made mention of that, it's definitely one of the big downsides to using them. Gotta protect yourself or you could do some serious damage (especially to the eyes). Also forgot to mention most people turn these lights off in the last few weeks of flowering to prevent the light from destroying any active alkaloids.
Ha, I was going to make a thread on this. I was doing a more comprehensive search on google to find some more info to help with the thread, and I found this on the second page. Of course after reading it, I remembered reading this before.
This definitely seems to be the way to go. THC has high capabilities of absorbing UV-B, protecting the plant from the radiation. The idea that the plant would produce more THC to protect it from its presence would seem reasonable. It should also be noted that HPS essentially provides no UV-B, which is most commonly used for indoor flowering. It would definitely seem that there would be a significant opportunity for THC production that is being lost without a source for UV-B.
The reptile lights would probably be the best source. You'd probably need a few unless you found one with a lot of watts (like this one). A tanning light would do it too, but would be pretty expensive I would assume.
I've heard that its best to not leave them on for more than four hours a day because UV-B is harmful to plants, but I would think this is something best determined through one's own experimentation. Simply turning them off when you're in the room, or having them on when one knows one won't be in the room, negates any threat to oneself.
Quote: coda said: Also forgot to mention most people turn these lights off in the last few weeks of flowering to prevent the light from destroying any active alkaloids.
I hadn't read this before. Do you remember where you found anything about that?
Do you plan on experimenting with this, coda? My friend is going to run with it when his grow starts, and later on, once he's involved with breeding and has formed a stable, consistent line, he'll try to do some comparison to find the difference. Simply putting the bulbs at one side of the grow room should be enough to see it as long as the other variables stayed consistent.
Quote: Sirius said: I've heard that its best to not leave them on for more than four hours a day because UV-B is harmful to plants, but I would think this is something best determined through one's own experimentation. Simply turning them off when you're in the room, or having them on when one knows one won't be in the room, negates any threat to oneself.
^ That is exactly what I was going to input into this thread. I've done a lot of reading about the addition of reptile UV lights in the grow room in the years past. Its best to keep them on a separate timer and have them come on for 4-6 hours in the middle of the photoperiod. So if you on a 12/12 and run the UV Fluorescents for 6 hrs, you would kick them on 3 hours after the lights turn on and 3 hours before them turn off. Most Metal Halide lamps have some UV-B but most of that is blocked by the glass on the cooled reflector.
That timing makes good sense, considering that the most UV-B a plant would be exposed to naturally would be in the middle of the day, since its the time that part of the Earth is closest to the Sun.
Do you know anything about what coda said regarding turning them off for the last few weeks of flowering? I don't know too much about this, but to me it seems counter-productive, since this would be the time that one would be seeking to maximize THC production the most.
Quote: Yes, but what is really important is the production of THC as well. Trichrome production doesn't necessarily equate into THC production.
Yes, i know this. I was just pointing out one of the benefits to the UV light. More trich's = more protection for your plants = healthier, happier, plants = more potent plants = ....etc
Quote: The reptile lights would probably be the best source. You'd probably need a few unless you found one with a lot of watts (like this one). A tanning light would do it too, but would be pretty expensive I would assume.
It really depends on the size of your grow tho. More plants and more sq ft = more uv lights needed. The grows i have seen usually have at least two lights in there. The lights themselves are relatively inexpensive so purchasing a couple won't put too big a dent in your pocket. Make sure to get the 10% UV bulbs tho, they're more efficient then the 5% ones.
Quote: I hadn't read this before. Do you remember where you found anything about that?
Well i haven't read anything specific on it. I'm just recanting what i've seen other growers do and use some logic. UV light degrades THC, this is why you don't dry your weed in the sun. When using UV lights in your grow there is a certain point where you want to stop using them because the trichromes aren't utilizing the light correctly. This happens when the trichs start going from cloudy to amber (towards the end of the cycle). At this point the actives are beginning to over mature anyways (amber trichs yadda yadda) so the extra UV light on them (IMO) just helps to further degrade the goodies in your plant. Here's a slightly better explanation:
Quote: The round head of the trich magnifys the uvb in late flowering stages until they cloud up and turn amber because they stop acting as magnifiers. Pot TV did a show recently that shed much lite on this subject.
What you said about THC production is true, BUT, it's because of the increased trichrome production that your THC levels are increasing.
Here's a whole thread dedicated to it on another site, i think they even link to the video you linked here.
Quote: Do you plan on experimenting with this, coda?
Yes my next grow will include 2-4 UV lights along with the HPS. FYI they do make 4 foot UV lights so you don't have to stick to the weenie reptile lights if you don't want to, i think they're just cheaper. After watching someones grow produce trichromes by the end of the first week was enough to convince me to buy some, then, reading up on WHY it was so just made it concrete that i HAVE to have these in my next flowering cycle.
This explains to me why a lot of older heads who grew with MV and MH lights say they're better then HPS. HPS lights put out ZERO UV light while MV and MH both out put a decent amount (more so with the MV light). Someone mentioned a suggestion that would work if you had the cash. A 150-250 watt MH light on a light mover would provide enough UV light for the grow without you having to buy a lot of small lights and/or move them around.
Either way my ladies will be getting bathed in UV light during my next grow and i'll have some hands on experience to report on.
I wonder how much UV light CMH bulbs put out. I used one on my last grow and they are very bright and very white. The manufacturer says this:
"The alumina arc tube, when operating, generates a considerable amount of ultraviolet radiation. The UV is filtered to acceptable levels by the glass outer envelope during normal use."
The lights put out a bunch of UV but whatever coating they use (presumably to protect you and your plants) will obviously diminish that to a level too low to be of much use. Some of those bulbs you can remove the coating, some can't, personally i say don't fuck with them and just buy something that's meant to put out UV rays.
Could you use a UVC bulb as a supplemental light at say a certain distance from your plants?
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Quote: Could you use a UVC bulb as a supplemental light at say a certain distance from your plants?
Don't think it would help, UVB light is what you want over them. The reptisun lights are pretty cheap, you can find them for about 10 bucks if you go to a local reptile/pet store. The big chains carry them too but at about 5-10$ more.
Quote: coda said: yes, i know this. I was just pointing out one of the benefits to the UV light. More trich's = more protection for your plants = healthier, happier, plants = more potent plants = ....etc
I was just throwing it out there since it hadn't been mentioned yet.
Quote:
It really depends on the size of your grow tho. More plants and more sq ft = more uv lights needed. The grows i have seen usually have at least two lights in there. The lights themselves are relatively inexpensive so purchasing a couple won't put too big a dent in your pocket. Make sure to get the 10% UV bulbs tho, they're more efficient then the 5% ones.
The cheap ones run at lower watts and can only penetrate a few inches. How many one would actually need, of course, just depends on the specifics of one's grow, like you said. I was just saying that one of the inexpensive bulbs alone probably isn't going to do it.
I also ran across an article on reptile lighting and pet supplies in general, regarding the lack of truth-in-advertising laws on the products. Here's an excerpt. There's also a list of ones that actually do produce UV-B.I don't know enough about any of this, but just tossing it out there as a grain of salt...
Quote:
The problems with truth in advertising goes beyond the misleading use of the term "full-spectrum". When it comes to UVB-producing fluorescents, the percentages given are not particularly useful as the manufacturers rarely tell you what that is a percentage of. If you have a light producing, for example, 20% of its total wavelengths in the UV range, and of that 10% is in the needed UVB range, while another light produces 40% of its wavelengths in the UV range, with 6 percent of that in the UVB needed range, the product with 6% of the 40% is going to produce more UVB in the needed UVB range than the other product. The product with "10%" on the package may look like the better light than the one that says "6%", but it isn't if that "10%" isn't providing enough UVB for your reptile.
Quote:
UV light degrades THC, this is why you don't dry your weed in the sun. When using UV lights in your grow there is a certain point where you want to stop using them because the trichromes aren't utilizing the light correctly. This happens when the trichs start going from cloudy to amber (towards the end of the cycle). At this point the actives are beginning to over mature anyways (amber trichs yadda yadda) so the extra UV light on them (IMO) just helps to further degrade the goodies in your plant. Here's a slightly better explanation:
Yes, definitely. It just sounded weird to me at first because of the "last few weeks", because the point at which the UV-B would stop being effective regarding our intended goal would be about the time one would be harvesting, but then I realized "well, sativas are going to have that process extended out over a further amount of time", and when to harvest is a matter of personal preference as well. But yes, certainly, once the trichromes are clouding over and aren't magnifying the light anymore, its time to stop.
Quote:
What you said about THC production is true, BUT, it's because of the increased trichrome production that your THC levels are increasing.
Actually this is the point I was arguing against. THC itself is doing the absorption. Of course the trichrome production increases and this further increases the production of THC, but I would have to assume that THC production within individual trichromes increases as well. If the amount of trichromes stayed the same with the introduction of UV-B light, the THC production within the amount that is there would still increase. I think this is supported by the idea that the amount of trichromes in general doesn't equate into high levels of THC, even though it is reasonably safe to assume as much with varieties of cannabis used as drugs.
Quote:
After watching someones grow produce trichromes by the end of the first week was enough to convince me to buy some, then, reading up on WHY it was so just made it concrete that i HAVE to have these in my next flowering cycle.
Exactly! It seems as logical as applying nutrients really.
Quote: The cheap ones run at lower watts and can only penetrate a few inches. How many one would actually need, of course, just depends on the specifics of one's grow, like you said. I was just saying that one of the inexpensive bulbs alone probably isn't going to do it.
I also ran across an article on reptile lighting and pet supplies in general, regarding the lack of truth-in-advertising laws on the products. Here's an excerpt. There's also a list of ones that actually do produce UV-B.I don't know enough about any of this, but just tossing it out there as a grain of salt...
That is an interesting read. I honestly can not say whether or not these lights put out the UV rays they claim to, i simply don't have the equipment to measure it myself. I'm sure with some digging we can find some more empirical data dealing with the UV output of the cheaper bulbs. The reptisun brand just comes highly recommended, it's easy to find, and easy on the wallet. Is it as good as something designed for, let's say, a tanning bed? Definitely not. However it may be adequate for cannabis growing. Remember that while UV light is beneficial, it also has the power to burn the living shit out of your plants. Have too strong a light and you'll end up being counterproductive, the plant won't be able to produce enough of it's defense mechanisms, and eventually it will start to suffer.
In that case having a light that isn't as strong would be a good thing. I can understand your concern with light penetration, but, considering how cheap these things are and how versatile they can be there's no reason not to add some to hit the lower portions of the plant. In fact you could take the 4' tubes, put two on top, and buy two more to place on opposite sides of the plants. this way you have light coming from the top and the sides.
Most of the grows i've read about using UV light use these reptisuns and they seem to do really well. I'm sure there are better models out there (you'd probably be best with a 150w MH), but these seem to work pretty well. So i wouldn't discount them right away.
Quote: Actually this is the point I was arguing against. THC itself is doing the absorption. Of course the trichrome production increases and this further increases the production of THC, but I would have to assume that THC production within individual trichromes increases as well. If the amount of trichromes stayed the same with the introduction of UV-B light, the THC production within the amount that is there would still increase. I think this is supported by the idea that the amount of trichromes in general doesn't equate into high levels of THC, even though it is reasonably safe to assume as much with varieties of cannabis used as drugs.
hmm, i'll have to go back and read up on the biochemical process again, but it was to my understand that it was the trichromes that absorbed the UV light and the plant then used that absorption to increase the levels of THC. I think we're thinking/saying the same things in just different words.
Quote: coda said: In that case having a light that isn't as strong would be a good thing. I can understand your concern with light penetration, but, considering how cheap these things are and how versatile they can be there's no reason not to add some to hit the lower portions of the plant. In fact you could take the 4' tubes, put two on top, and buy two more to place on opposite sides of the plants. this way you have light coming from the top and the sides.
I agree with you completely on all of these points. I was just saying that it wouldn't take just one of these bulbs, but possibly a few. My friend is planning on using the inexpensive reptile ones, anyhow.
Quote:
hmm, i'll have to go back and read up on the biochemical process again, but it was to my understand that it was the trichromes that absorbed the UV light and the plant then used that absorption to increase the levels of THC. I think we're thinking/saying the same things in just different words.
I'll read up more on this as well soon, but from what I've been reading, its THC that absorbs the UV-B light, the trichrome simply collecting it and magnifying it to the disc cell or something like that.
I happened upon some more discussion about UV-B on another site and I thought I'd post here for our collective another more expensive bulb, complete with ballast ($75). Its more expensive than the common pet shop UV bulbs, but it claims to produce similar amounts of UV-B light as the sun, when its at the right distance, and there is actual data on the UV-B output. They also assert it produces very little heat. My friend doesn't have any intention of trying it out, at least anytime soon, but I thought I'd throw it out there since it seems more capable of producing UV-B light at levels resembling natural sunlight (from which location on the planet I'm not sure though ). I'll keep an eye on the posts of the guy who is planning on using it on a mover and see what kind of results he gets.
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Of course after reading it, I remembered reading this before. 
