projectinfo
Well-Known Member
They say on the site that uvb is 320-290
Bridgelux EB Series Build
- Thread starter brahbbyB
- Start date
projectinfo
Well-Known Member
@nfhiggs
@Serva, @Randomblame
have you found a need for uv-b spectrum on these strip lights?
Worth it?
^
@Serva, @Randomblame
have you found a need for uv-b spectrum on these strip lights?
Worth it?
^
Dachem2010
Well-Known Member
Its actually 280 but the atmosphere filters out anything below 290
projectinfo
Well-Known Member
projectinfo
Well-Known Member
I dont use it too and i agree, same here man
Dachem2010
Well-Known Member
Quite a few studies of up to 30% thc increase
Humple
Well-Known Member
See, that's my thing too. I don't doubt that UV can increase cannabinoids and terpenes, but I have no need for that, as what I'm growing is every bit as good as the stuff I used to buy from the dispensary. Now I'm aware that some of that could be placebo caused by confirmation bias, but even if that's true, who cares? If it works, it works. Maybe one of these days I'll get bored and then I might get the itch to tinker with some new toys, but until then, I'm good to go.
Dachem2010
Well-Known Member
I guess I always try to do better then I am doing always need to excel
Dachem2010
Well-Known Member
If nobody tried to do better technology and the world would be at a stand still caveman status
Randomblame
Well-Known Member
I'm still using my 3ft. reptile bulb with 12% UVB(30% UVA) because I need to make a new fixture for the Agromax I've already laying around.
The given values like 440μW / cm² at 1' are average values and are valid for an area of 1x 4 ' but directly below the tube it is much stronger. I use the reptile bulb currently about 12-18" above the canopy and for the full 12h cycle and have on average only about 80-120μWs/cm². Thats only a dose of 3,5-5,2kJ/m² but despite the relatively low level the effect is clear and strong but there have already been deformations on some random seeds. I've postet a test in one of the UVB threads and they recommended a daily dose of 6,7-13,4kJ/m² and the results have shown that THC levels increase with higher UVB levels. But to get a daily dose of 13,4kJ/m² you need to provide ~310μWs/cm². UVB seems to be mostly absorbed by THCacid (trichome and inside the leafes) and seems not to harm the plant tissue but the high levels of UVA of these bulbs seems to cause stress.
The problem is, I've not enough height available in my little stealth-box and the fixture is to big to hang the bulbs above. I'm forced to use it at the same height.
For this reason I will build a kind of "adjust the wing" reflector just for T5 bulbs and use a small 10x 10mm perforated alu L-channel at 5mm distance(3mm holes, 3mm shift) in front of the bulb which should work like a "super-spreader". One part of the light goes thru the holes the other one will be reflected to the reflector wings. (see below)
This way one could reduce the intensity directly under the bulbs and the whole light is much better distributed acoss the canopy. The reflector is relatively easy to bend and reflector sheet metal (standard stucco, uncoated) I already have laying around from another project. To bend a 20mm wide strip of perforated aluminum sheet in 90° L-channel shape with 10x 10mm without the corresponding workbench is not so easy as it sounds. My neighbors will for sure not be grateful if I hammer the whole day with the blacksmith's hammer, lol! Maybe I'll just use a closed 10x 10mm L-channel which one can already get in such small sizes on e3ay and at 2' distance from the canopy the girls in the center anyway get enough reflected UVB also without holes inside the alu spreader.
I'll let you know when it's ready to use and I'll share my experience with the Agromax bulbs. But it will take some time, sorry. I've started another run a few weeks ago and I got driver issues with one of my Meanwells thats need to be figured out and resolved. I think the new reflector is a job for the winter break. The reptile bulb has just run for ~500h and is practically new. Unfortunately she is too big for my 3sft veg area but I already know who I give it to.
If you can handle your environmental conditions and consistently get good results then I do not see any reason not to use UVB. Even good reptiles bulbs give good results and can literally run all day long while the Agromax bulbs are so strong that you have to be careful and probably need a minute timer to not harm the plants.
If only runs 15min. per hour you save 75% power and the bulbs age more slowly. In addition, a 1500h old Agromax still produces more UVB than a 12% reptile bulb of the same size.
For beginners T5 reptile bulbs like Arcadia D3 desert(12%) or D3 dragon(14%) bulbs are perfect. They cause no visible stress but they provide enough UVB to feel the difference and what is best, 2ft. and 4ft. Agromax bulbs fits in the same housing and use the same ballast(24w or 54w).
The given values like 440μW / cm² at 1' are average values and are valid for an area of 1x 4 ' but directly below the tube it is much stronger. I use the reptile bulb currently about 12-18" above the canopy and for the full 12h cycle and have on average only about 80-120μWs/cm². Thats only a dose of 3,5-5,2kJ/m² but despite the relatively low level the effect is clear and strong but there have already been deformations on some random seeds. I've postet a test in one of the UVB threads and they recommended a daily dose of 6,7-13,4kJ/m² and the results have shown that THC levels increase with higher UVB levels. But to get a daily dose of 13,4kJ/m² you need to provide ~310μWs/cm². UVB seems to be mostly absorbed by THCacid (trichome and inside the leafes) and seems not to harm the plant tissue but the high levels of UVA of these bulbs seems to cause stress.
The problem is, I've not enough height available in my little stealth-box and the fixture is to big to hang the bulbs above. I'm forced to use it at the same height.
For this reason I will build a kind of "adjust the wing" reflector just for T5 bulbs and use a small 10x 10mm perforated alu L-channel at 5mm distance(3mm holes, 3mm shift) in front of the bulb which should work like a "super-spreader". One part of the light goes thru the holes the other one will be reflected to the reflector wings. (see below)
This way one could reduce the intensity directly under the bulbs and the whole light is much better distributed acoss the canopy. The reflector is relatively easy to bend and reflector sheet metal (standard stucco, uncoated) I already have laying around from another project. To bend a 20mm wide strip of perforated aluminum sheet in 90° L-channel shape with 10x 10mm without the corresponding workbench is not so easy as it sounds. My neighbors will for sure not be grateful if I hammer the whole day with the blacksmith's hammer, lol! Maybe I'll just use a closed 10x 10mm L-channel which one can already get in such small sizes on e3ay and at 2' distance from the canopy the girls in the center anyway get enough reflected UVB also without holes inside the alu spreader.
I'll let you know when it's ready to use and I'll share my experience with the Agromax bulbs. But it will take some time, sorry. I've started another run a few weeks ago and I got driver issues with one of my Meanwells thats need to be figured out and resolved. I think the new reflector is a job for the winter break. The reptile bulb has just run for ~500h and is practically new. Unfortunately she is too big for my 3sft veg area but I already know who I give it to.
If you can handle your environmental conditions and consistently get good results then I do not see any reason not to use UVB. Even good reptiles bulbs give good results and can literally run all day long while the Agromax bulbs are so strong that you have to be careful and probably need a minute timer to not harm the plants.
If only runs 15min. per hour you save 75% power and the bulbs age more slowly. In addition, a 1500h old Agromax still produces more UVB than a 12% reptile bulb of the same size.
For beginners T5 reptile bulbs like Arcadia D3 desert(12%) or D3 dragon(14%) bulbs are perfect. They cause no visible stress but they provide enough UVB to feel the difference and what is best, 2ft. and 4ft. Agromax bulbs fits in the same housing and use the same ballast(24w or 54w).
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nfhiggs
Well-Known Member
Link to such studies? That are not YouTube "side by ides", but real actual university studies, that is.
wietefras
Well-Known Member
I think he is referring to a university study:
"UV-B RADIATION EFFECTS ON PHOTOSYNTHESIS, GROWTH AND CANNABINOID PRODUCTION OF TWO Cannabis Sativa CHEMOTYPES."
What they forget to mention is that that test used a very high dose of UV to reach that maximum result. 72W/m2 of UV bulb. With a pretty much linear relation between UV light intensity and THC delta (pun intended). So if you use a lot less then the effect is a lot less too.
Now what would happen if you add 72W of regular light per m2? You might get say 20% more yield. Not sure I'd take a THC increase over a yield increase.
Plus I wonder if the plants don't yield less because of the UV. If you make them struggle to survive the UV for a THC response, wont that detract from actual yields. Don't remember if the article mentioned something about that.
Dachem2010
Well-Known Member
Since cannabis is still federally illegal there is few studies on it because it is so hard to get approved to study a scheduled one narcotic but here are some that have to do with cannabis and other plants clearly the plants have a UVR8 protein which when exposed to UV light get broken down and it signals the plant to start repairing and increasing flavonoids phytohormones chlorophyll and others.
Pate, David W. (1983). "Possible role of ultraviolet radiation in evolution of Cannabis chemotypes". Economic Botany 37 (4): 396–405. doi:10.1007/BF02904200
2) * Lydon, John; Teramura, Alan H. (1987). "Photochemical decomposition of cannabidiol in its resin base". Phytochemistry 26 (4): 1216–1217. doi:10.1016/S0031-9422(00)82388-2
3) * Lydon J, Teramura AH, Coffman CB (1987). "UV-B radiation effects on photosynthesis, growth and cannabinoid production of two Cannabis sativa chemotypes". Photochemistry and Photobiology 46 (2): 201–206. doi:10.1111/j.1751-1097.1987.tb04757.x. PMID 3628508
4) * Beentje, Henk (2010). The Kew Plant Glossary. Richmond, Surrey: Royal Botanic Gardens, Kew. ISBN 978-1-84246-422-9
Pate, David W. (1983). "Possible role of ultraviolet radiation in evolution of Cannabis chemotypes". Economic Botany 37 (4): 396–405. doi:10.1007/BF02904200
2) * Lydon, John; Teramura, Alan H. (1987). "Photochemical decomposition of cannabidiol in its resin base". Phytochemistry 26 (4): 1216–1217. doi:10.1016/S0031-9422(00)82388-2
3) * Lydon J, Teramura AH, Coffman CB (1987). "UV-B radiation effects on photosynthesis, growth and cannabinoid production of two Cannabis sativa chemotypes". Photochemistry and Photobiology 46 (2): 201–206. doi:10.1111/j.1751-1097.1987.tb04757.x. PMID 3628508
4) * Beentje, Henk (2010). The Kew Plant Glossary. Richmond, Surrey: Royal Botanic Gardens, Kew. ISBN 978-1-84246-422-9
- Effects of Ultraviolet-A Exposure on Ultraviolet-B induced Accumulation of Specific Flavonoids in Brassica napus. Kenneth E. Wilson, John E. Thompson, Norman P.A. Huner and Bruce M. Greenberg
- The effect of ultraviolet radiation on the accumulation of medical compounds in plants. Wen Jing Zhang and Lars Olaf Bjorn
- There are many more besides Steve they have to do without cannabis but cannabis has the same uvr8 protein that gets activated when it is exposed to UV radiation so clearly if you're there not being exposed to those wavelengths the plant is missing out on a natural spectrum of sunlight that he has evolved with over millions of years yes you can grow good shit without it but are you growing the best you could be?
nfhiggs
Well-Known Member
See, now that does not sound like something "beneficial" to me. Its obvious that UV is damaging to plants - and as Wietefras points out, gains in potency would likely be offset by yield loss. I've said before, the evidence *is* compelling, but IMO, it falls short of being convincing.
Dachem2010
Well-Known Member
It's not breaking it down as your thinking uvb hits a dimer protien the tryptophan molecules in it get energized because they absorb that wavelength causing hydrogen bonds to break thus activating the protein the plant also has a pathway to put the monomers back into the dimer UVR8 causing a signaling cascade In the plant but I'm no long going try to explain things to people who wont look outside there cave it's a pet peeve of mine people hold an opinion without research
Humple
Well-Known Member
And what opinion would that be?