UVB/Cannabis science report

[mr. childs]

400 watts of 10,000k ran all day will fry plants. Been there and done that!
And $50 for a 250 watt bulb plus a 250 watt ballast to drive it.

how close was the bulb? i have ran the 400w cheapie bulbs from amazon @10k, 14k, 15k @12/12 for a week without frying plants. i was trying to replicate the things that @RM3 & @Illumination r.i.p.(i think) were doing, using actinic bulbs

 

[Heil Tweetler]

(PLEASE NOTE THIS IS NOT MY POST ORIGINAL POSTER TETRAHYDROCANNA LOCATED FORM A DIFFERENT WEBSITE)





The estimates below is my own estimations based on article mentioned below and actual research on the matter.

Article: UV-B RADIATION EFFECTS ON PHOTOSYNTHESIS, GROWTH AND CANNABINOID PRODUCTION OF TWO Cannabis Sativa CHEMOTYPES.
By: JOHN LYDON, ALAN H. TERAMULA and C. BENJAMIN COFFMAN.
Department of Botany, University of Maryland, College Park, MD 20742, USA.

My estimated conclution: "Add 2 x 23w UVB lights / m2 to your grow room and increase THC levels up to 30% in buds."

Read this science article regarding UVB lights effect on drug type cannabis originated from high heigted tropical areas with highly elevated UVB levels. In experiments with plants they have shown an increase of THC concentration levels in leaves from in a range from 22% - 48% depending on UVB intensity. In flower trichomes they got an increase between 15% - 32%. Thats staggering news! Now, this is laboratory conditions with UVB lights flitered to emitt in 300 nm wavelenght UVB light. It's widely known that THC UVB absorption properties range between 280 - 315 nm, so that is important. There's no longer any doubt in my mind that UVB boosts the THC potency of drug type cannabis, and that dont having UVB light is not realising the full potential of our dear plants! Time for a change imho!

What id like to do is to get an estimate on how indoor growers could reproduce this results at home. To get an estimate on what lights, how much lights, and so on, wich could be beneficial. According to the scientists they used 240w UVB, but i dont know on how big of an area. The scientists says that 13,4 KJ / m2 is the level of UCB used in their trials, and that is as much as the UVB levels in 3000m altitude in mountains where strong marijuana is found to grow. According to the article marijuana grown in these UVB rich areas has a 33% increased THC content compared to the same marijuana grown at sea level.

Looking at wikipedia, i found that 1w = 3600 J (3,6KJ), but that seems a bit high compared to the ammount used by scientists, so I devided it to 0,36 KJ instead thinking i made some error somewhere. If i divide 240w (amount UVB scientist used) in 5m2, i get roughly 72w/m2, wich is around 14KJ according to my estimates, and that fits exactly and seems to be a fair estimate, so i think im on the right track here! Then, a 13w UVB light would give 4,5 KJ. Thats what i use, and that seems a bit lesser than needed. 2 x 23w UVB / m2 in the right spectrum should to the trick to produce massively strong cannabis with approximately up to 30% increased THC production in buds! I noticed the UVB bulb I use has the perfect spectrum for cannabis, repti glo 10.0. They come in 13w and 23w strength, and is avalible in sorted zoo shops.

Repti glo 10.0 UV spectrum chart:

It need to be stressed that UVB light is harmful to humans and plants that dont have developed defences to it (like cannabis has). When having such a bulb in the grow room, it need to be switched of when entering to room. Cancer is a known effect of UVB light exposure.

Peace
Tetra

That article is 30 years old. Apparently it wasn't very convincing.
Adding your "estimation based on actual research"

 

[jarvild]

how close was the bulb? i have ran the 400w cheapie bulbs from amazon @10k, 14k, 15k for 12/12 for a week with frying plants. i was trying to replicate the things that @RM3 & @Illumination r.i.p.(i think) were doing, using actinic bulbs

3'+ from the canopy. And what was your conclusion of trying to match their style?

 

[mr. childs]

it worked, frosty plants, but smaller harder nugs. i once even used the agromax pure uv for an entire 12/12 grow. uvb works well, very well, but will bite you in the arse if its on too long.

 

[Yodaweed]

more so you think than mdhj?

Unsure, but i know it works

 

[mr. childs]

Unsure, but i know it works

i still use jaz rose spray, too lazy to buy hedione & make my own

 

[jarvild]

it worked, frosty plants, but smaller harder nugs. i once even used the agromax pure uv for an entire 12/12 grow. uvb works well, very well, but will bite you in the arse if its on too long.

I,m using it more to get my trich's to finish in a normal fashion. Got a few hybrids that just don't want to finish to that 70-80% cloudy window I like for harvest without the flowers being well over ripe. This is where I feel the best benefit of running UVB comes in. A better balance of the overall maturity of the trich's.

 

[Bob Dobelina]

Been using reptile bulbs 10.0, six per meter, about 9-12 inches out. This seems to be sufficient to provide fairly even coverage for a square meter, and it does appear to produce more trichromes and a more potent finished product based on personal experience. Somebody mentioned this article being old. U. Maryland was (maybe still is) the federal research facility for cannabis. It's a safe bet the folks running the studies weren't interested in helping the general public grow danker nugs, which is probably why it was lost in time for so long (check an old Mel Frank grow guide from the late 80's, you'll find nothing about UV in there). That said, I'm in a legal state and I'm planning to do a side by side with identical clones, nutes, lights, ect and take samples to a lab, so if/when that happens I'll report back with some more recent homegrown science. Prolly not 'til next winter 'cause I just started my last winter grow and I shut down indoors and move outdoors in the Summer. The reading I've done seems to indicate it's still as effective if you don't run 'til the last few weeks, so I start it at the beginning of flower with 1 hour, add an hour every 10 days to gradually harden them off to the UV 'til I'm up to 4 hours for the last few weeks. I have found horticultural uv/full spectrum t-5's that have more UVB, as well as less green and more blue and red spectrum than the reptile bulbs, so when these CFL's burn out I'm going to invest in a few. There are also pure UV horticultural bulbs, but reading forums about these it appears that more than 15 minutes at a time will burn your plants. One guy posted a picture of his sunburn from working under them for 20 minutes. So less electricity, but if you could use a little bump in the rest of the spectrum I'd go with the others so you've got a little more fudge factor in time and height along with a bit of added PAR. As for LED's that claim to have UVB LED bulbs, I have yet to find an LED chip that produces UVB, they're all in the UVA "blacklight" range. Also, if they're behind lenses or glass almost all the UV is filtered out, so as best I can determine LED UV bulbs are basically worthless for increasing potency, you've got to have some sort of bare florescent or remove the glass from your metal halide (sketchy, be careful not to accidentally spray a bare hot HID bulb when you're foliar spraying or it'll pop and you'll have a grow, and maybe a face, full of broken glass). I have noticed with these reptile bulbs that if the other limiting factors aren't dialed they can burn a plant at 9 inches, so you may need to raise the height if you're not 100% with nutes, temp, co2, and keeping them optimally watered. PS, side note, I read an article in Cannabis Business Times recently that did some tests on optimal umols. Previously folks were assuming it was the same as tomatoes (1000) but the study cited showed 1500 umol at 86 degrees was optimal for sativas for peak photosynthesis. Presumably it could be a bit lower for hybrids or indica dominants since indica's evolved further from the equator where sunlight is less intense, but they also found that up to 2000 was fine with no burning or slowing of growth. I don't run CO2 but I grow in a fairly tight 11,000 cubic foot home that's occupied by an average of 3 adults 24 hours a day. People produce about a kg of CO2 a day through respiration, so that's about 7-ish pounds of CO2 added to 11,000 cubic feet every day. I lb=20 cubic ft of pure CO2, so at this rate I could turn over all the air in the house 6 times daily and still stay well over 1000ppm of CO2, so it seems like I'm probably well over the 1300ppm where photosynthesis peaks in cannabis even accounting for incidental air exchange with the outdoors and plant respiration from my small personal grow. Don't have a CO2 meter to back all this up, but I can verify my plants can take a lot more light when running in the low-mid 80's than they can running in the mid to high 70's, I can get about 3 inches closer without burn at the higher temps, which seems to confirm my hypothesis. So, my current strategy is to ride the lightning with mid 80's and 1500 umol 'til the last 10 days, then drop the temps to 75 by bringing down the umol from the lights to around 1000. I started this with my grow that's currently flowering. Just beginning the 4th week of flowering so I can't speak to end results, but the flower growth has greatly exceeded previous grows so far. http://magazine.cannabisbusinesstimes.com/article/january-2017/the-key-to-maximum-yield.aspx

One last request: I know the internet's anonymity lends itself to a lot of shit talking and cock measuring, but if y'all could keep it to a minimum on weed forums it makes my research go a lot faster. Thanks.

 

[Kingrow1]

Unless you have a real full spectrum (not led crap) UV does very little if anything. Now whilst your repeating a decade of failure to make it work with sub par spectrums CMH has evolved and tweaked the initial problems and become the leading contender for UV. Get yourself one or just give up because 99% of all recent science supports the full spectrum being he only increase in plant growth in any study with this particular plant species....

Been using reptile bulbs 10.0, six per meter, about 9-12 inches out. This seems to be sufficient to provide fairly even coverage for a square meter, and it does appear to produce more trichromes and a more potent finished product based on personal experience. Somebody mentioned this article being old. U. Maryland was (maybe still is) the federal research facility for cannabis. It's a safe bet the folks running the studies weren't interested in helping the general public grow danker nugs, which is probably why it was lost in time for so long (check an old Mel Frank grow guide from the late 80's, you'll find nothing about UV in there). That said, I'm in a legal state and I'm planning to do a side by side with identical clones, nutes, lights, ect and take samples to a lab, so if/when that happens I'll report back with some more recent homegrown science. Prolly not 'til next winter 'cause I just started my last winter grow and I shut down indoors and move outdoors in the Summer. The reading I've done seems to indicate it's still as effective if you don't run 'til the last few weeks, so I start it at the beginning of flower with 1 hour, add an hour every 10 days to gradually harden them off to the UV 'til I'm up to 4 hours for the last few weeks. I have found horticultural uv/full spectrum t-5's that have more UVB, as well as less green and more blue and red spectrum than the reptile bulbs, so when these CFL's burn out I'm going to invest in a few. There are also pure UV horticultural bulbs, but reading forums about these it appears that more than 15 minutes at a time will burn your plants. One guy posted a picture of his sunburn from working under them for 20 minutes. So less electricity, but if you could use a little bump in the rest of the spectrum I'd go with the others so you've got a little more fudge factor in time and height along with a bit of added PAR. As for LED's that claim to have UVB LED bulbs, I have yet to find an LED chip that produces UVB, they're all in the UVA "blacklight" range. Also, if they're behind lenses or glass almost all the UV is filtered out, so as best I can determine LED UV bulbs are basically worthless for increasing potency, you've got to have some sort of bare florescent or remove the glass from your metal halide (sketchy, be careful not to accidentally spray a bare hot HID bulb when you're foliar spraying or it'll pop and you'll have a grow, and maybe a face, full of broken glass). I have noticed with these reptile bulbs that if the other limiting factors aren't dialed they can burn a plant at 9 inches, so you may need to raise the height if you're not 100% with nutes, temp, co2, and keeping them optimally watered. PS, side note, I read an article in Cannabis Business Times recently that did some tests on optimal umols. Previously folks were assuming it was the same as tomatoes (1000) but the study cited showed 1500 umol at 86 degrees was optimal for sativas for peak photosynthesis. Presumably it could be a bit lower for hybrids or indica dominants since indica's evolved further from the equator where sunlight is less intense, but they also found that up to 2000 was fine with no burning or slowing of growth. I don't run CO2 but I grow in a fairly tight 11,000 cubic foot home that's occupied by an average of 3 adults 24 hours a day. People produce about a kg of CO2 a day through respiration, so that's about 7-ish pounds of CO2 added to 11,000 cubic feet every day. I lb=20 cubic ft of pure CO2, so at this rate I could turn over all the air in the house 6 times daily and still stay well over 1000ppm of CO2, so it seems like I'm probably well over the 1300ppm where photosynthesis peaks in cannabis even accounting for incidental air exchange with the outdoors and plant respiration from my small personal grow. Don't have a CO2 meter to back all this up, but I can verify my plants can take a lot more light when running in the low-mid 80's than they can running in the mid to high 70's, I can get about 3 inches closer without burn at the higher temps, which seems to confirm my hypothesis. So, my current strategy is to ride the lightning with mid 80's and 1500 umol 'til the last 10 days, then drop the temps to 75 by bringing down the umol from the lights to around 1000. I started this with my grow that's currently flowering. Just beginning the 4th week of flowering so I can't speak to end results, but the flower growth has greatly exceeded previous grows so far. http://magazine.cannabisbusinesstimes.com/article/january-2017/the-key-to-maximum-yield.aspx

One last request: I know the internet's anonymity lends itself to a lot of shit talking and cock measuring, but if y'all could keep it to a minimum on weed forums it makes my research go a lot faster. Thanks.

 

[jimihendrix1]

1000w Hortilux x 315w CMH x 2 Solacure UVA/UVB per 4 x 4.




Specifications:

FR40T12 multi-wattage, multi-peak UVB/UVA horticultural lamp.
Wattage: 32-40 watts standard, can be run as high as 80w for special applications.
Color: white to violet. Color temperature >10,000K
Dimension: 4 foot by 1.5 inches. Will fit almost any shop light.
Reflector: Built inside the lamp. No external reflector needed.
UVA/B: 5x the power of the SG-1 and Universal UV. About 20 to 50x the power of reptile lights.
UVA/B rating: Equivalent to a 30% UVB lamp, but we do this in very different frequencies, so they don't equate.
Life: 1000 hours at 70% of original power.

From the ground up, this lamp was engineered to do nothing but operate as a horticultural lamp. It can operate as low as 25 watts and as high as 80 watts, but is centered to us a standard 4 foot 32w fixture and it's own timer. It is four foot long, 1.5" in diameter, so it can be used in virtually every 4 foot fixture at the hardware store. Our entire goal was to make it simple and cheap to operate. All the really interesting things are happening inside the lamp, not in the fixture.

Again we licensed Sol Glass for this lamp, like our SG series lamps. It is more transparent to any other UV glass made, and allows transmission of UVB between 280nm and 300nm, something other lamps don't do well.




This is one reason our lamps have been so successful in the labs, testing for resin/flavonoids/terpenes/THC. The new spectrum uses many of the same spectral peaks as the SG, but are 3 to 4 times stronger in the UVB, while still having a solid UVA profile. UVA is seldom discussed in many circles, and it is too large a topic to discuss here, but we design our lamps with a sun similar UVA spectrum because we have good reason to think it is also very beneficial for UV started plants. The UVA to UVB ratio is very different than the sun, however, as the effective ratio is about 4 times higher than the sun. This is why you can use half as many lamps and still get twice as much UVB. In short, you use few lamps farther from from your plants. This makes using them easier and cheaper for you, while being more effective. It is hard to overstate how big a leap this lamp is.

 

[whitebb2727]

I prefer to use uv. I even like the Agromax 10,000k+uva t5 bulbs. I ran them the whole grow.

Agromax makes a pure in bulb. It is powerful. It needs to be 3 foot from the canopy. It also needs a separate timer. 15 min on each hour.

I notice a difference in plant growth and potency when using uv.

 

[Kingrow1]

This reads more like the stuff ive read, rep + for applying yourself

1000w Hortilux x 315w CMH x 2 Solacure UVA/UVB per 4 x 4.




Specifications:

FR40T12 multi-wattage, multi-peak UVB/UVA horticultural lamp.
Wattage: 32-40 watts standard, can be run as high as 80w for special applications.
Color: white to violet. Color temperature >10,000K
Dimension: 4 foot by 1.5 inches. Will fit almost any shop light.
Reflector: Built inside the lamp. No external reflector needed.
UVA/B: 5x the power of the SG-1 and Universal UV. About 20 to 50x the power of reptile lights.
UVA/B rating: Equivalent to a 30% UVB lamp, but we do this in very different frequencies, so they don't equate.
Life: 1000 hours at 70% of original power.

From the ground up, this lamp was engineered to do nothing but operate as a horticultural lamp. It can operate as low as 25 watts and as high as 80 watts, but is centered to us a standard 4 foot 32w fixture and it's own timer. It is four foot long, 1.5" in diameter, so it can be used in virtually every 4 foot fixture at the hardware store. Our entire goal was to make it simple and cheap to operate. All the really interesting things are happening inside the lamp, not in the fixture.

Again we licensed Sol Glass for this lamp, like our SG series lamps. It is more transparent to any other UV glass made, and allows transmission of UVB between 280nm and 300nm, something other lamps don't do well.




This is one reason our lamps have been so successful in the labs, testing for resin/flavonoids/terpenes/THC. The new spectrum uses many of the same spectral peaks as the SG, but are 3 to 4 times stronger in the UVB, while still having a solid UVA profile. UVA is seldom discussed in many circles, and it is too large a topic to discuss here, but we design our lamps with a sun similar UVA spectrum because we have good reason to think it is also very beneficial for UV started plants. The UVA to UVB ratio is very different than the sun, however, as the effective ratio is about 4 times higher than the sun. This is why you can use half as many lamps and still get twice as much UVB. In short, you use few lamps farther from from your plants. This makes using them easier and cheaper for you, while being more effective. It is hard to overstate how big a leap this lamp is.

 

[Kingrow1]

I prefer to use uv. I even like the Agromax 10,000k+uva t5 bulbs. I ran them the whole grow.

Agromax makes a pure in bulb. It is powerful. It needs to be 3 foot from the canopy. It also needs a separate timer. 15 min on each hour.

I notice a difference in plant growth and potency when using uv.

I agree uv has its benefits but mainly in full spectrum. Not mainstream to me yet but certainly thats why cmh has given another possible edge to it over hps and part spectrum bulbs. Im very much not an led fan when they make these claims.

Very intresting with some of the new tech lights coming out that this subject might become more mainstream as it certainly hasnt gained much ground with many growers upto now

 

[whitebb2727]

I agree uv has its benefits but mainly in full spectrum. Not mainstream to me yet but certainly thats why cmh has given another possible edge to it over hps and part spectrum bulbs. Im very much not an led fan when they make these claims.

Very intresting with some of the new tech lights coming out that this subject might become more mainstream as it certainly hasnt gained much ground with many growers upto now

That's what I ran with the t5. Full spectrum. I ran a mix of bloom, veg, pure par and 10k+uva.

 

[OldMedUser]

One last request: I know the internet's anonymity lends itself to a lot of shit talking and cock measuring, but if y'all could keep it to a minimum on weed forums it makes my research go a lot faster. Thanks.

What kind of researcher writes a whole page of text in one single, almost unreadable block. Ever hear of paragraph breaks or white space?

I didn't bother reading any but the first line or two.

 

[MichiganMedGrower]

I agree uv has its benefits but mainly in full spectrum. Not mainstream to me yet but certainly thats why cmh has given another possible edge to it over hps and part spectrum bulbs. Im very much not an led fan when they make these claims.

Very intresting with some of the new tech lights coming out that this subject might become more mainstream as it certainly hasnt gained much ground with many growers upto now

Ed Rosenthal published results of added uv increasing thc levels many years ago. He proved it using HPS and Metal Halide lamps. No full spectrum lamps like today available then.

There are reports of commercial growers only adding uv finishing bulbs like the 10k Solis tech one for only the last 2 weeks for up to 5% thc increases when testing the same strains.

They had the same results when running uv full cycle.

Sorry I don’t have the links from my research it was 2 years ago.



We are recently seeing proof of uva influencing flavonoids and terpenes. And there is a lot of individual light wavelength studying going on at the university of Michigan now. Using discreet colored diodes. They are learning to control plant growth and output from customizing the light spectrum.

Say goodbye to full spectrum led pretty soon. They will have specifically engineered new style “Blurple” lamps next. With uv and far red likely included for our plants.

 

[Kingrow1]

That's what I ran with the t5. Full spectrum. I ran a mix of bloom, veg, pure par and 10k+uva.

I can totally agree to that

 

[Kingrow1]

Ed Rosenthal published results of added uv increasing thc levels many years ago. He proved it using HPS and Metal Halide lamps. No full spectrum lamps like today available then.

There are reports of commercial growers only adding uv finishing bulbs like the 10k Solis tech one for only the last 2 weeks for up to 5% thc increases when testing the same strains.

They had the same results when running uv full cycle.

Sorry I don’t have the links from my research it was 2 years ago.



We are recently seeing proof of uva influencing flavonoids and terpenes. And there is a lot of individual light wavelength studying going on at the university of Michigan now. Using discreet colored diodes. They are learning to control plant growth and output from customizing the light spectrum.

Say goodbye to full spectrum led pretty soon. They will have specifically engineered new style “Blurple” lamps next. With uv and far red likely included for our plants.

I just cant support much led data, they are limited even with these full spectrums. Too many years of twisting data with no real results. Cmh has made them redundant in many big growshops here, dont even stock them anymore and have disclaimers saying that they lied in the first place.

Would you choose led over cmh at the prices they charge anyway.

Fingers crossed cmh lives up to the hype, looks good initially, when i replace mt hps thats my first choice

 

[MichiganMedGrower]

That's what I ran with the t5. Full spectrum. I ran a mix of bloom, veg, pure par and 10k+uva.

Weird question for this topic but have you ever run all bloom style 3k red tubes for flower?

All of this light science is true but it is not as useful to the plant as a good intense red light heavy spectrum for flowering.

I got higher potency and yield from the 600w hps than the Phillips 315 3100k every test round

I have gone with 2 hps 600’s and 1 315 cmh in a tight pattern for best yield and quality. The cmh brings out the colors and seems to help finish them slightly faster. And the plants seem to like the overlap area best. Not sure how to quantify that they like it but you can see it in the room after trying all these combinations.

 

[whitebb2727]

Weird question for this topic but have you ever run all bloom style 3k red tubes for flower?

All of this light science is true but it is not as useful to the plant as a good intense red light heavy spectrum for flowering.

I got higher potency and yield from the 600w hps than the Phillips 315 3100k every test round

I have gone with 2 hps 600’s and 1 315 cmh in a tight pattern for best yield and quality. The cmh brings out the colors and seems to help finish them slightly faster. And the plants seem to like the overlap area best. Not sure how to quantify that they like it but you can see it in the room after trying all these combinations.

I have. I did a couple runs of the stock 3000k, a couple runs with stock 6500k and then mixed spectrum.

In my opinion I prefer pot grown with mixed spectrum with uv. My next favorite was the all 6500k though it lacked some yield. The 3000k did better as far as yield but I didn't prefer it.

I don't sell but I smoke with friends and give a little bud away here and there. Their comments led me to believe they liked the mixed spectrum better as well.