FADING-SILHOUETTE
Well-Known Member
What height from the canopy and for what duration are people getting the best results from UVa and UVb..? -FS/STELTHY 
THC, CBD, Terpene test results – UVA vs UVB vs none
- Thread starter Prawn Connery
- Start date
FADING-SILHOUETTE
Well-Known Member
What duration and how close to the canopy for those T8? UV tubes..? FS
Prawn Connery
Well-Known Member
@Frank Cannon is the best person to ask, but from memory he runs the UV lights 12/12 – same as the boards – and he hangs them about 40-45cm from the canopy.
ChiefRunningPhist
Well-Known Member
I noticed every setup having FR added as well as some having some R added too, but the Highlight boards didn't have any of the added R or FR, though the highligts did have UVA like every other board or setup (minus the 3×3 which I wouldn't really call a control).As some of you might know, former member Or_Gro did a side-by-side comparing three different types of LED boards with supplementary UV reptile bulbs. He also did a control grow without any UV at all. The test results are interesting because UV clearly works – an increase of almost 20%!
But perhaps the most surprising thing is, you don't need UVB to do it. UVA and near-UV (400-420nm) appear to be just as effective.
The following are the results comparing a 4'x4' tent full of QB96 boards and a 4'x4' tent full of QB288 boards – both of which had 30% UVA and 6% UVB supplements (fluorescent reptile bulbs) – and a 4'x4' tent full of High Light boards and a 3'x3' with QB96 boards, both of which had no supplementary UV.
The High Light boards do have a small amount of UVA and some near-UV (400-420nm) incorporated into the boards themselves (Sunlike 415nm-pump LEDs).
The 3'x3' served as the baseline, as it had no UV or near-UV.
6 x QB96 Elite, 1 x 28 diode FR bar, 2 x 4’ T5 30% UVA & 6% UVB
Total THC: 19.8%
Total CBD: 0.7%
Total Terpenes: 4.7%
8 x QB288, 4 x QB35, 1 x 28 diode FR bar, 2 x 4’ T5 30% UVA & 6% UVB
Total THC: 18.7%
Total CBD: 0.63%
Total Terpenes: 5.0%
8 x High Light UV
Total THC: 19.1%
Total CBD: 0.64%
Total Terpenes: 4.8%
Control – 3'x3' room with 4 x QB96, 4 x rapidled FR pucks, NO UV
Total THC: 16.6%
Total CBD: 0.52%
Total Terpenes: 3.9%
I think we can safely say that UV works. However, UVA and near-UV (400-420nm) seems to work just as well as UVB. Empirical evidence, my friends
According to the science more red equates to more mass while less red equates to smaller yield and more cannibinoid density (to a point and amoung other things). If you had the PPFD of all the rooms at equal canopy intensity, then it stands to reason that 3 out of the 4 had more red/FR making up for the total portion of light than the Highlight did, which had nothing added. This means I see the results as being an indicator of the total SPD ratio (R:B, ect), rather than a comparison of the difference in THC% between UVB and UVA treated plants. When looked at in this way, your test seems to comply with other tests of similar nature done by experts (attached is a common piece of literature cited). Imo if you'd want to determine the difference in effectiveness between UVA and UVB, then you'd have to control for the base spectrum. You'd have to use a base SPD that you then would add either-or UV too.
Tests that I think would be more compelling to the point you're trying to make:
Perhaps try Highligts with UVB and without.
Perhaps try QB 288 3000k with nothing added, then with only UVA added, then with only UVB added, and then with both added. Then run 3 more the exact same way (only UVA, only UVB, both), but with FR added ontop, as well as a room with only FR and the QB288. This would tell you more definitively what effect the suppliments had compared to each other, and when blended. Clones off the same mother would be expected but sounds like you're already doing.
Perhaps try a highlight without anything added and then with FR added.
The more % of your total light that's taken up by FR will create less non-FR light to grow with. I'd have to digitize the SPDs and calculate %'s to know for certain the difference in ratios between the setups, but at first glance it looks like 3 of the 4 have more FR and/or R, while 1 of the 4 had no FR (disregarding the 3×3).
I'm also curious to see all the rooms if that's possible? Also what wattages? It seems like you're pumping quite a bit in there, the plant can absorb more UVB if the intensity is high. How much UVA did Orgro measure out of the Arcadias at canopy compared to the highlights at canopy? UVB at canopy?
EDIT:
What were the CCTs of the 288's? Do you know FR chips used and power per FR light in the grows? Power and chip of QB35 (I couldn't find a QB35 anymore)? What reptile bulb was he using?
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ChiefRunningPhist
Well-Known Member
2.79lbs in a 4'×4'? That's over 11oz per plant!
4'×4' = 16ft2
1m2 = 10.76ft2
1400 - 1500 PPFD
1450μmol/s·m2 × (1m2/10.76ft2) × (16ft2)
=
2156μmol/s
2156μmol/s ÷ 730W = 2.95μmol/J
2156μmol/s ÷ 674W = 3.27μmol/J
2156μmol/s ÷ 666W = 3.24μmol/J
Horselover fat
Well-Known Member
That is not what the science says.
Prawn Connery
Well-Known Member
Hey mate, the High Lights had no added UVA or any other supplements. They ran straight up. The boards do include a very small amount of UVA and a moderate amount of near-UV (400-430nm). The CRI94 spectrum puts them heavy on the red, deep red and far red (620+nm) compared to typical CRI80 based strips and boards.
So this was a comparison of UVA + UVB vs near-UV vs no near-UV or UV.
3000K CRI80 was the "Base SPD" for the straight QB288s. They had no near-UV, UVA or UVB. They also lacked Far Red and had very little 630nm and 660nm compared to the other boards.
The QB288s + UV reptile bulbs compared "Base SPD + UVA/B". They also included red monos to boost yield.
The QB96s were 4000K CRI70/630/660red + UV and were higher in blue. So they really compared "UVA/B + Blue" with red monos for yield.
The High Light 3000K CRI94 compared full spectrum phosphor-coated white including "near-UV" with the "Base SPD" and "Base SPD + UVA/B".
The results at face value show you can increase cannabinoid and terpene levels with near-UV alone over the Base SPD (no near-UV) and Base SPD + UVA + UVB + near-UV. At face value, it appears adding UVA and UVB over near-UV provides no benefit, and that adding more blue (around 450nm) with added UVA, UVB and near-UV has the greatest benefit.
These were not scientific test. My hat is off to Or_Gro for managing four different 12-week grows consistently for as long as he did. You won't see many better side-by-side comparisons outside a lab.
I need to mention that FR doesn't take up any % of PAR as it's measured from 400-700nm. 730 is photosynthetically active, but it acts on different phytochromes. Plants should be able to absorb it in addition to equal amounts of other spectra, assuming all things being equal and leaf temperatures remaining normal.
Here's the QB35 spectrum:
Prawn Connery
Well-Known Member
Looking at those 12-week grows, I would definitely believe those yields. I've consistently pulled more out of a 4x4 with 2x 600HPS bulbs hung vertically, so I know it can be done. And the gpw are honest too: 1.8gpw for the High Lights, 1.74gpw for the 288s and 1.84gpw for the 96s.
As for the PPFD, that is my quote but it wasn't based on those wattages. It was what Or_Gro said he was aiming for initially with CO2. The maths doesn't add up, I agree. But those figures would indicate an average 1000+ PPFD across each tent, peaking higher (1200-1300 PPFD) in places. Maybe he ran out of CO2 at the end of the grow – I dunno. It's not clear in Or_Gro's thread and he no longer posts there.
OK Edit: I just went through the thread and found a reference to 1000 PPFD. So that would be more accurate. Still not sure if that is a bunch of spot readings or average over each tent, as UV and Far Red wouldn't be included in the PAR readings.
Prawn Connery
Well-Known Member
Red + Far Red does appear to have an effect on leaf and other plant mass, including flowering yields, whilst Blue and near-UV do appear to have a positive effect on cannabinoid and terpene production. But it also appears possible to increase both with the right ratios. Then there is the question of whether blue increases cannabinoid and terpene production by the observed figures, or if it mostly has an effect on yield that – by default – increases the percentages of THC etc in relation to the reduced weight. I have seen studies supporting all these theories and my own experience is that there maybe a bit of truth in everything.
But the interesting thing about Or_Gro's results were the dry weight yields were all very similar, indicating the cannabinoid and terpene tests were based on samples that were of similar weight and structure. To me, that's an important indication of the effect of light on cannabinoid and terpene levels.
Humple
Well-Known Member
I've been waiting for someone to provide the hard data which proves that increased far red has any effect on flower mass (I'm talking about data that's based on properly scientific studies, i.e., repeated, consistent results). So far, what I've seen are references to studies which show that far red increases leaf and stem mass, as if that must equate to an increase in flower production as well. I'm not stating that you must be incorrect, but nor am I anywhere near convinced that you're correct. But if you have such data, I'd love to see it!
ChiefRunningPhist
Well-Known Member
Well that's what I've been seeing. I'm not a PhD, and I'd welcome some contradictory data to my observation.
These graphics came from the study posted previously...
Intensities were maintained between the SPD's and the ones that did the best in terms of cannibinoid density had more blue, while the one with the biggest yield had almost no blue. When you swap some of the red for blue, or when you reduce red to allow more of your intensity be blue, it seems your yield drops and your cannibinoid intensity increases.
Attached is a second example (biased maybe) showing reduced red to increase terpenes.
There's another research paper I can't find atm but it also summarized that red light increased inflorescence size/weight of shortday flowers in greenhouses. Ill have to try to find.
It looks to me that more red increases size and weight while more blue increases cannibinoid content at the risk of a bit of reduced yield. This is why I'm saying that the tests conducted don't really affirm a UVA being equal to UVB in terms of cannibinoid development, but rather the tests showed that more blue in your SPD will increase cannibinoid development over predominantly red, or blue lacking.
Prawn Connery
Well-Known Member
Maybe you need to look more?
I just did a quick search and found few studies and experiments. I'm too wasted to get into it now, but I've read a few.
The Impact of DLI, Light Quality and Photoperiod on Bedding Plant Flowering Response - Greenhouse Product News
Successful scheduling of annual bedding plants for specific market dates requires an understanding of how plants respond to temperature, light intensity and quality and photoperiod. In this article we will focus on daily light integral (DLI), light quality and photoperiod. Most floriculture...
gpnmag.com
Far-red radiation increases dry mass partitioning to fruits but reduces Botrytis cinerea resistance in tomato
The addition of far-red (FR, 700–800 nm) radiation to standard growth light triggers a set of photomorphogenic responses collectively termed shade avo…
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Prawn Connery
Well-Known Member
LOL! That's my favourite study. The High Light board was modelled partly on that study.
Humple
Well-Known Member
Maybe I need to look more? As in quickly Google for studies? (Your snark aside, I do appreciate the effort.)Maybe you need to look more?
I just did a quick search and found few studies and experiments. I'm too wasted to get into it now, but I've read a few.
The Impact of DLI, Light Quality and Photoperiod on Bedding Plant Flowering Response - Greenhouse Product News
Successful scheduling of annual bedding plants for specific market dates requires an understanding of how plants respond to temperature, light intensity and quality and photoperiod. In this article we will focus on daily light integral (DLI), light quality and photoperiod. Most floriculture...
Far-red radiation increases dry mass partitioning to fruits but reduces Botrytis cinerea resistance in tomato
The addition of far-red (FR, 700–800 nm) radiation to standard growth light triggers a set of photomorphogenic responses collectively termed shade avo…www.sciencedirect.com
That second link you provided shows precisely why this subject needs far, far more study before growers or light manufacturers start making definitive claims. Though they state (and fairly so) that their addition of far red resulted in increased dry fruit mass, they also happen to cite one study which found an increase which was "not statistically significant", and yet another study which showed that additional far red actually decreased the dry fruit mass. So I remain unconvinced.
I'm very happy that you, GLA, Amare, and all the other experimenters out there are trying these different ratios and working toward more real-world data, but... It's early days for claims, in my opinion.
OneHitDone
Well-Known Member
Grow any non-cannabis plant and your eyes will open
ChiefRunningPhist
Well-Known Member
I've only seen the highlight room, and while a nice crop I'm just not quite convinced aha but I'm trying to give benefit of doubt. 2.8lbs from 1000 PPFD *whistle*...
I think the 600W HPS are the most efficient size, and 2 makes 1200W in a 4×4.
1200W × 2.0 = 2400μmol/s
2400/16×10.76 = 1,614PPFD, so when you were pulling 2.0+ from a ~4×4 (honestly you'd have to measure the surface area inside the cylinder of your grown screen to determine sqft) you were about 2/3 more light as these guys were getting.
Ya I guess without seeing the relative SPDs side by side its hard for me to agree with that sentiment. Did you guys make any calcs to determine your R + FR wattages needed to match the high light? Or calcs to determine UVA matching of highlight? What about measuring UV from the fluoros compared to the UV of the highlights or measuring the R and FR compared to the highlights? I'm just not convinced the SPDs were close in comparison at this moment in time, but I'll quit cluttering your thread. I just was curious when I saw the title and clicked, but of course I have to be "that guy" lol. Despite what I'm uncertain of, it looks like the boards grow the plant well, and that highlight room was pretty nice looking too. Good work.
Humple
Well-Known Member
Haha, poor Prawn has two skeptics on his case today. Prawn, buddy, don't take it personally! You're a good dude and you and your peeps at GLA have undoubtedly put out a very interesting and worthy product in the High Light boards. I give this same shit to Hybridway/Amare when he's talking spectrum effects.
OneHitDone
Well-Known Member
How large is your grow area and what species of plants do you grow under electric lights?
PoopyMcPooper
Member
An informative video if you have the time. He starts talking about light spectrum's and its effect on cannabis at 18 minute mark
Prawn Connery
Well-Known Member
Mate, here I was trying to relax and enjoy my buzz before I went to bed, and then you came along and made me go all Google-fu on your arse!
Only Joking
Alright, I admit I didn't read all those before I posted. But both those studies point to increased fruiting yields and accelerated flowering with an increase in the far red to red ratio. There's also a lot of anecdotal evidence that growers have collected over decades showing high-red spectrum HIDs always outyield low-red spectrum lamps. The most obvious example of this is MH vs HPS.
In my experience (and other growers' experience for that matter), HPS always outyields MH – and that is a direct comparison of flowering yields in cannabis plants. The interesting thing about the MH-HPS comparison is that HPS not only has a greater percentage of red light than MH, it actually has a higher red:far red ratio. What this means is that, although it has been proven that lowering R:FR ratios (up to a ratio of 1.15:1 if I remember correctly) improves flowering and fruiting yields, as well as leaf and other biomass in plants, HPS still outperforms MH – even though it is at a R:FR ratio disadvantage.
Now some of you might be wondering if HPS has a higher R:FR ratio than MH, why do MH plants grow more compact than HPS? Isn't a lower R:FR ratio supposed to elicit more shade avoidance and thus more stretch?
The answer is in the high amount of blue, near-UV and UV in MH that counters the shade-avoidance response.
That just leaves the higher amount of red light in HPS as the likely driver of higher flowering yields. And that is what old-skool growers have been observing for years – even if it's just anecdotal evidence.
Also, think about this. A large proportion of cannabis flowers or "buds" is made up of stem and stalk. As we all know, stem and stalk adds weight to buds. A tight bud structure has less stem/stalk than a loose bud structure. If both structures have the same amount of bracts/calyxes, then the looser structure will weigh more. This is something that has also been observed in Metal Halide vs HPS grows.
Now remember that higher levels of red and far red (including higher ratios of far red – which goes a little bit against what I'm saying, but bear with me . . . ) elicit the shade avoidance response in plants that causes stem and petiole elongation whilst promoting larger, thinner leaves. This is an environmental response (primarily a response to increasing ratios of far red to red light in the lower canopy) that allows the plant to not only grower taller to where there is more sunlight, but to harvest more photons to fuel that growth. A larger, thinner leaf after all, has a greater surface area to capture light, but has the same mass (energy required) as a smaller, thicker leaf.
It's ingenious when you think about it, because the plant actually morphs into a different shape to make the best use of the limited light it has. The plant actually makes itself more efficient, and that transformation is driven by the R:FR ratio.
But if you want to know something even MORE interesting, there are studies showing that certain strains of cannabis show little to NO response to changes in R"FR ratios. This study quotes a strain known as "G-170" (whatever that is) that is "insensitive to changes in the R:FR ratio, and no effect on flowering has been observed (Magagnini et al., 2018)."
So if some strains are insensitive to changes in R:FR then what else could account for the difference in yield between high-red spectra such as HPS and low-red spectra such as MH?
You tell me. Just don't go all Google-Fu on my arse
Now I'm going to smoke a big, fat bong because all this science shit has taxed my puny prawny brain
