Should I add UVB Light?

DennisBrown · Apr 6, 2021

Moe.Red said:
I'm trying!

I can tell you even the plants under UV are showing signs of distress in the leaves, but the buds are still A1 quality. But I think that is more about the strain than the grower in this case.

Also, it seems that our original hypothesis that the UVR8 response is local to the area hit by UV seems to be holding up. I think that a dense canopy under UV will show results only in the areas directly in the path of UV, lower buds will probably not be effected. This might require a staged harvest where the tops are taken and lower buds are then allowed to further ripen now that they are getting UV. Dunno, it's still early.

I don't have hard data (which is hard to do for this) but anecdotally speaking, the whole plants SEEMS to benefit some if most of the plant is getting UV, so the lower and mids get some bump, but not nearly as much as the buds that are getting direct UV. It's one of those things we get conflicting feedback on, although most say it helps. It may very well be strain specific, or a false reading due to a lack of hard data. My guts says it probably helps some at least with some strain.

Milson · Apr 6, 2021

Moe.Red said:
I've been thinking about how to measure yield. I don't think I can do it cleanly. What is yeild exactly?

Dry weight?
Amount of resin / oz of plant material?
Cannabinoid density / oz?

I think yield means different things to different growers.

And what if you say its cannabinoid / oz, but the THC goes up and others go down, meaning net zero. Is that better yield?

I think the term yield is spurious and will be difficult to quantify. Right up there with how high this makes you. We are venturing into the zone of beauty is in the eye of the beholder and we are unlikely to achieve a specific result that works as a blanket statement.

I think.

Yield is dry weight flower in @sshz case, but it could absolutely be resin for someone making concentrate or an individual cannabinoid even for extracts (the idea!).

I think the approach of "here is exactly what I did and what happened" is perfect for people to understand the experiment and take away something useful for their situation.

Moe.Red · Apr 6, 2021

DennisBrown said:
I don't have hard data (which is hard to do for this) but anecdotally speaking, the whole plants SEEMS to benefit some if most of the plant is getting UV, so the lower and mids get some bump, but not nearly as much as the buds that are getting direct UV. It's one of those things we get conflicting feedback on, although most say it helps. It may very well be strain specific, or a false reading due to a lack of hard data. My guts says it probably helps some at least with some strain.

Perhaps a different growing style than mine would lend itself more to whole plant illumination. Hell UV gets blocked by glass, those photons don't have a chance to get lower into my canopy. Thats yet another variable.

I look at it like photosynthesis a bit, the UVR8 response should only occur in the presence of UV. The energy to excite the protein comes from the UV photon. If there is no UV at the bottom of the plant, I'm not sure how that would help down there except perhaps a hardening of the entire plant, or perhaps resources inside the plant being re-routed to handle the burn protection response. My gut would see that as detrimental overall.

There is just a lot we just don't know here.

In my case, I don't know how I would begin to quantify this effect, so we will end up with yet another anecdote at best.

Moe.Red · Apr 6, 2021

Milson said:
I think the approach of "here is exactly what I did and what happened" is perfect for people to understand the experiment and take away something useful for their situation.

10-4

I will also use the press to measure the difference in resin from the same start weight of cured top colas - both UV and not UV.

We are getting cannabinoids from the TLC testing.

I don't see a reliable way to quantify yield in dry weight with this test being multiple branches on the same plant. You would need a time machine to go back and change the UV parameters on the same bud and test. I'll get to work on the time machine later this week, gotta get to that sock drawer cleanup first tho.

Milson · Apr 6, 2021

Moe.Red said:
I don't see a reliable way to quantify yield in dry weight with this test being multiple branches on the same plant. You would need a time machine to go back and change the UV parameters on the same bud and test. I'll get to work on the time machine later this week, gotta get to that sock drawer cleanup first tho.

Yeah i agree this won't be a test that provides a clear data point for yield. You would need to be doing whole plants.

That said, it will still be a data point.

MIMedGrower · Apr 6, 2021

DennisBrown said:
I don't have hard data (which is hard to do for this) but anecdotally speaking, the whole plants SEEMS to benefit some if most of the plant is getting UV, so the lower and mids get some bump, but not nearly as much as the buds that are getting direct UV. It's one of those things we get conflicting feedback on, although most say it helps. It may very well be strain specific, or a false reading due to a lack of hard data. My guts says it probably helps some at least with some strain.

I’m still waiting for any data on your claim of an 8% thc increase. Surely in all these years you have compiled something?

I would think you would know if the effect on the uvr8 gene was local or systemic?

Please directly answer any question at this point or admit you are not sure.

from the Utah universities recent testing they are not sure the uv alone is as important to cannabinoid production as other blue light waves.

which makes sense since even with no uvb at all I have had my weed tested at over 25% thc.

and that’s just with single ended hps enclosed behind glass. You are claiming I could have had 33% weed?

C’mon now.

Let’s see some proof please! Ed rosenthal claimed this almost 30 years ago. I have only seen negative results online from adding uvb.

even the uvb in cmh seems to make plants stress in tents compared to my hps, my or fluorescents. That’s just my observation though.

Milson · Apr 6, 2021

30 years ago they also had no idea how thc synthesis worked compared to now. Thcas was discovered more recently than that. The previous hypothesis involved a longer chain with cbd earlier than thc iirc. Pretty different.

The above is from marijuana botany.

The claim it impacts thc exclusively is just silly. It's not even the claim given the structural changes.

It would have to be avoiding cbg at this point. It seems very unlikely not to have an effect.

If people want to have an argument about copywriting then whatever. Just seems besides the point.

This, by the way, fits into every common sense way I can think of w.r.t. what makes good weed: full expression of the plant's genetics, with 100% fullness being the expression in a hotspot like hawaii, colombia, thailand, panama, etc.

Moe.Red · Apr 6, 2021

Milson said:
30 years ago they also had no idea how thc synthesis worked compared to now. Thcas was discovered more recently than that. The previous hypothesis involved a longer chain with cbd earlier than thc iirc. Pretty different.

View attachment 1110670 View attachment 1110671

The above is from marijuana botany.

The claim it impacts thc exclusively is just silly. It's not even the claim given the structural changes.

It would have to be avoiding cbg at this point. It seems very unlikely not to have an effect.

If people want to have an argument about copywriting then whatever. Just seems besides the point.

This, by the way, fits into every common sense way I can think of w.r.t. what makes good weed: full expression of the plant's genetics, with 100% fullness being the expression in a hotspot like hawaii, colombia, thailand, panama, etc.

Are you trying to say that stuff from 50 years ago (quoted as gospel, settled science by some here) might be wrong? Peeshaw I say.

DennisBrown · Apr 6, 2021

Indiva710 said:
Research: Wavelengths Beyond PAR in Cultivation

Discover new findings on non-PAR light wavelengths and their effect on plant physiology, performance, and overall cultivation strategies.

fluence.science

Fluence just sent me this which kinda talks about what I was saying but no data other than a few graphs which I have here..
I also asked them if I could get the actual data from the uv part...

Hey Dennis have you noticed any difference on the time of day to run the uv of even at night as I believe you told me that the uv is not bright enough to effect their photo period but I'm not positive..
There's 20 pics sorry if I clogged it up but it was all the main info from the hour long webinar and thought it can contribute and save some ppl time I mean there's some other stuff that they talked about not in slides and is still a great listen...

As to when to run UVB, I'm not sure it matters. I've had several people test different times of the day, and the results were the same. Walter P. Haze, one of my testers, screwed up once and ran them from 12:00 to 2:00, but AM instead of PM. He didn't notice until he went to harvest. The plants didn't go to veg, and he said they came out exactly like he would expect. Now, that doesn't mean that every strain won't get triggered to veg, but the bulbs put out very, very little visible light.

I have had people tell me they were convince early on was better, or later on was better, but this was only their theory, nothing to back it up with. My gut says anywhere in the middle of the day is probably best, but since the whole point is simply to trigger the plant into defense mode, it just might not matter and my pet theory may be just as wrong as theirs. Regardless, I tell customers we aren't sure but anywhere in the middle of the day just makes sense to me. I think if it made a huge difference, we would know by now.

DennisBrown · Apr 6, 2021

Moe.Red said:
Perhaps a different growing style than mine would lend itself more to whole plant illumination. Hell UV gets blocked by glass, those photons don't have a chance to get lower into my canopy. Thats yet another variable.

I look at it like photosynthesis a bit, the UVR8 response should only occur in the presence of UV. The energy to excite the protein comes from the UV photon. If there is no UV at the bottom of the plant, I'm not sure how that would help down there except perhaps a hardening of the entire plant, or perhaps resources inside the plant being re-routed to handle the burn protection response. My gut would see that as detrimental overall.

There is just a lot we just don't know here.

In my case, I don't know how I would begin to quantify this effect, so we will end up with yet another anecdote at best.

UVR8 sends chemical messages to the mother plant, so the whole plant is "aware", but does it react? I think it does some and have reason to think so, but I can't prove it. One other thing to remember about UVB is that it is a much smaller wavelength, so the penetration power is zero. In fact, it only penetrates the top 3 or 4 layers of human skin. UVA goes another layer or two. UVC, maybe two.

I do have a couple of customers that I know ran UVB bulbs (much lower UVB, "Universal UV" 7%) straight up and down in a tent, in two opposing corners, and rotated the plants each day, so most of the plant was getting some light. They ran 12 hours a day, and these were tiny grows, 3x3 tents or smaller, and while they are happy with the results, there isn't any control to compare to. That bulbs doesn't have the pretty spectrum that the Flower Power does, but still does some good. A couple more customers use FP overhead and with side fills, but many growers aren't keen on sharing their methods and results. With anyone. They keep buying bulbs, however.

Milson · Apr 6, 2021

Milson said:
30 years ago they also had no idea how thc synthesis worked compared to now. Thcas was discovered more recently than that. The previous hypothesis involved a longer chain with cbd earlier than thc iirc. Pretty different.

View attachment 1110670 View attachment 1110671

The above is from marijuana botany.

The claim it impacts thc exclusively is just silly. It's not even the claim given the structural changes.

It would have to be avoiding cbg at this point. It seems very unlikely not to have an effect.

If people want to have an argument about copywriting then whatever. Just seems besides the point.

This, by the way, fits into every common sense way I can think of w.r.t. what makes good weed: full expression of the plant's genetics, with 100% fullness being the expression in a hotspot like hawaii, colombia, thailand, panama, etc.

Thinking about it, this is a pretty important distinction. If you think it's most likely cbd is a precursor to thc, you would expect to see them go up together. When they did not, you might theorize that is the breakpoint.

If you understand, as we do now, that cbg is a common precursor to thc, cbd, and cbc, with thcas, cbdas, and cbcas--enzymes not yet discovered at the time of this working hypothesis for the rosenthal studies but which scientists have now not just isolated but found the loci for the genes for--driving conversion between cbga and thca, cbda, and cbca respectively, it might color how you analyze the results.

In fact, a slight uptick in cbd in a 20:1 thc/cbd strain would be consistent with the model with the activating enzymes. There's not even really a discrepancy to solve for. Just a question about CBG and cbc, which I haven't heard any results either way for in part because they may have been mostly absent in the cultivars studied to date due to differences in the genetics behind, for instance, the cbcas enzyme, which I saw a study point out is oft-deleted in the cultivars sequenced so far.

Aqua Man · Apr 6, 2021

But we all know a plant can transport many of the compounds it produces ro where it needs. So in my mind I also feel that yeah more UVB typically will reach the exposed tops its not to say it won't benefit the entire plant... much like photosynthesis it's overall exposure we are looking for so canopy management in these circumstances is not only beneficial but crucial for best results. This would not only allow for much more overall exposure to those receptors but also a much more even intensity reducing the variances of over exposure in some areas and under in others.

I believe UVB should like all light be used on a DLI type schedule and making the most of it through even canopy training. We all really need to stop looking at photosynthesis at the locations and concentrate on overall plant photosynthesis.

Milson · Apr 6, 2021

Milson said:
Thinking about it, this is a pretty important distinction. If you think it's most likely cbd is a precursor to thc, you would expect to see them go up together. When they did not, you might theorize that is the breakpoint.

If you understand, as we do now, that cbg is a common precursor to thc, cbd, and cbc, with thcas, cbdas, and cbcas--enzymes not yet discovered at the time of this working hypothesis for the rosenthal studies but which scientists have now not just isolated but found the loci for the genes for--driving conversion between cbga and thca, cbda, and cbca respectively, it might color how you analyze the results.

In fact, a slight uptick in cbd in a 20:1 thc/cbd strain would be consistent with the model with the activating enzymes. There's not even really a discrepancy to solve for. Just a question about CBG and cbc, which I haven't heard any results either way for in part because they may have been mostly absent in the cultivars studied to date due to differences in the genetics behind, for instance, the cbcas enzyme, which I saw a study point out is oft-deleted in the cultivars sequenced so far.

This stream of thought brought to you by haze.

I have plants with an active cbcas enzyme as shown by tlc (haze and widow both). If the hypothesis that there is a single cbcas gene is correct, then when i crossed it with a non-cbc showing plant it would be halved as a ratio and I would expect a half-functional expression...it could be null without double positive but I'm suspicious given how 1:1 thc/cbd strains work. But then when i F2'd that, i should get the 1:2:1 punnet square ratio (showing full cbc as in haze, half cbc as in, maybe Chemdog x haze, and then in the F2 i would get some with the same cbcas expression as, in this example, chemdog (none))....and if i did that would be freaking incredible knowledge to spread widely in the community because breeders could use that to consciously breed in the oft-absent cbc enzyme to strains with it absent while selecting to keep as much else about the strain intact through the F2 selection. Kind of some milson mendel action (I'm joking to be clear, i think this would just be confirming existing results lol).

And it could be tested for easily with tlc.

This could also be tested by just F2ing a 1:1 thc/cbd strain and seeing what you get w.r.t. cannabinoid expression across a population of seed grown plants.

Seems like I would learn something. Might be able to talk some growers into helping me test too....if I have an example of each expression and the effect is noticable, could get some noisy data by describing the effect within that genetic makeup without the need for other growers to do tlc....

Tuck it away.....

Moe.Red · Apr 6, 2021

Milson said:
If you understand, as we do now, that cbg is a common precursor to thc, cbd, and cbc, with thcas, cbdas, and cbcas--enzymes not yet discovered at the time of this working hypothesis for the rosenthal studies but which scientists have now not just isolated but found the loci for the genes for--driving conversion between cbga and thca, cbda, and cbca respectively, it might color how you analyze the results.

I'm trying hard to remain neutral in this whole thing and just collect the data. Both you and Aquaman make interesting points, but ultimately we just don't know. Pieces of the puzzle are missing.

I'm will report the facts as I see them and try hard not to color the results by trying to prove or disprove any theory specifically. But when this test is over, I'm gonna have fun diving in and trying to understand the data with the backdrop you guys are talking about. Fun fun.

Milson · Apr 6, 2021

Moe.Red said:
I'm trying hard to remain neutral in this whole thing and just collect the data.

In order to ensure a lack of bias, you could collect each sample and mark them clearly, but then leave the room and have one of your kids switch the position and marker around however they want and then write down the true identity of each sample with each marker and you only get to know the identity once you are analyzing the result (they write it down immediately after doing it and you can't look until you are done).

It improves the data (or protects against subconscious bias) and contributes to family science time!

You could record video of your child messing with the samples and markers if you don't trust them to remember which is which.

Moe.Red · Apr 6, 2021

Milson said:
In order to ensure a lack of bias, you could collect each sample and mark them clearly, but then leave the room and have one of your kids switch the position and marker around however they want and then write down the true identity of each sample with each marker and you only get to know the identity once you are analyzing the result (they write it down immediately after doing it and you can't look until you are done).

It improves the data (or protects against subconscious bias) and contributes to family science time!

You could record video of your child messing with the samples and markers if you don't trust them to remember which is which.

Boy you are a fart smeller. Oh, sorry smart feller!

Moe.Red · Apr 6, 2021

So this is an interesting result. The control bud is growing around the marker pin and the UV side is not.

Day 7 Control Bud

Day 7 Control

Day 7 UV Bud

Day 7 UV

Day 1 Control

Day 1 UV

I had to take the photo from a higher angle than the previous day to even get the small pin in frame. I've got tons of shots of everything in the can if we need to refer back to anything, including the same angle as before.

Yesterday was a good day for the gals, VPD, PH, Temp, everything was like I was shooting darts. I did a 30 gallon water change and added nutes last night, so they got a nice drink of properly proportioned everything. Growing conditions could not have been much more stable for this entire flower period. Bacterial colony is thriving. Dosed all micros one last time with the water change.

I'm pleased overall with the plant.

I have stuck to 45 minutes the last 2 days. I feel like the plants are no longer reacting negatively to the UV, and in some cases have even bounced back. The control side is just putting on mass like nobody's watching how fat she is getting.

This one is the center cola for the tent getting UV in the range between the UV side and Control side, but also getting blasted directly under a 1000W HPS. A bit of light stress there but still getting chubby, so

BTW - that little magnetic gauge in the back is way wrong.

It seems appropriate to me to either keep the photoperiod the same or increase it, but I'm listening for advice here.

Moe.Red · Apr 6, 2021

Oh yeah, with the other plants - I have 2 Purple Kush growing one each on either side of the test plant. The one under UV has a distinctive purple tinge to it, the other is still very green. It's really hard to get proper pics under these HPS lights, so I need to wait for the wife / photographer to come down and help me with this white balance so I can display that. She's currently under the influence of heavy CBN trying to sleep thru a migrane, so maybe tomorrow.

Side quest! UV confirmed drives anthocyanins? Stay tuned and have your decoder ring handy!

Milson · Apr 6, 2021

Moe.Red said:
It seems appropriate to me to either keep the photoperiod the same or increase it, but I'm listening for advice here.

I say increase it and we watch. Maybe an hour fifteen? Hour Thirty? I'm kind of expecting to want to go back down as a senescence effect increases anyway (and/or we see damage), but maybe not. I very highly doubt any damage will have significant longer term effects if we go back down or have a cloudy day upon damage.

Moe.Red · Apr 6, 2021

I did the mix up thing so I did not know what was what, but I kinda still did a little. The kief was obvious.

I'm moving down to 3 lanes on the next one to make sure we get proper circles on each lane.

Should I add UVB Light?

Should I add UVB Light?

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