More THC testing – UVA vs UVB vs near-UV

[Grow Lights Australia]

We took four samples of the same strain, all grown in coco run-to-waste by competent growers under slightly different lighting set-ups, with two of the samples being provided by the same grower under the same conditions, but grown six months apart (to compare the ageing process or "cure"). This experiment sought to duplicate, or at least compare with, an earlier test conducted by @Or_Gro and posted up by @Prawn Connery here: https://www.rollitup.org/t/thc-cbd-terpene-test-results-uva-vs-uvb-vs-none.1001617/

The strain was a local eight-week Afghan-Skunk variety that had been shared amongst three growers. This makes the experiment a little bit more variable than the Or_Gro test, but it was the best we could do locally given legal constraints. The samples were marked "A", "B", "C" and "D" and the tester was not provided with any other information.


Sample A
Grown under eight Grow Lights Australia "High Red" boards with 4x Arcadia 6/30% UVB/UVA lamps running 12 hours a day (full 12/12 cycle) averaging 1000 PPFD. Coco run-to-waste, Canna nutrients. Here is the spectrum.



You cannot see the UVB in the above spectral reading, but here is what the 6% Arcadia bulb looks like.




Sample B
Four High Light UV boards averaging 1000 PPFD. Coco run-to-waste, Canna nutrients. This sample was about seven months old. Here is the spectrum.




Sample C (same as Sample B)
Four High Light UV boards averaging 1000 PPFD. Coco run-to-waste, Canna nutrients. This was a fresh sample less than one month old. Here is the spectrum.




Sample D
Two High Red Boards, two 315CMH lamps, averaging 1000 PPFD. Coco/perlite run-to-waste, Hygen nutrients. Here is the spectrum.




Samples B and C were grown and provided by @Prawn Connery, who also did the PPFD testing and supplied the spectrographs. Sample A was grown by a local RIU member, and Sample D was grown by a friend of Prawn's.

 

[Grow Lights Australia]

Here are the results.


SAMPLE.......CBDA.......CBD.......CBGa.......CBG.......CBN.......d9THC.......THCa

A...................................................2.2%........2%.........................4.4%.........14.3%


B...................................................0.9%........0.2%.......0.1%......5.8%..........21.3%


C...................0.1%.......................0.7%........................0.1%......1.4%..........24%


D...................0.2%.......................1%...........................0.1%......2%.............22.7%



Core Sample A



Core Sample B



Core Sample C



Core Sample D

 

[lukio]

good stuff. even i can understand that!

 

[Grow Lights Australia]

According to the lab, as THCa is a precursor to d9THC, the following calculations apply to get the total THC count:

THCa x 0.87 + THC = total d9THC

From this formula we get the following %

Sample A = 16.8% d9THC

Sample B = 24.3% d9THC

Sample C = 22.3% d9THC

Sample D = 21.7% d9THC


Often you will see labs simply combining THCa + THC to get the total d9THC percentage, but apparently this is wrong, as some THCa is lost during decarboxylation (or maybe that is the ratio of THCa conversion to d9THC 100:87).

What is interesting is the UVB sample had the lowest THC levels but almost four times the CBG levels of the other samples. There was not a lot of difference in the other samples, but that is to be expected as two of them (B and C) were grown under the same lights, and the remaining sample (D) was grown under a mix of CMH and High Red that provided similar near-UV and UVA levels (slightly more UVA) .

There are a couple of theories on why the UVB sample was so low. The first is that the UVB being on for 12 hours straight was breaking down the THCa faster than the plant was increasing it in response to the added stress. The lab technician had a theory that the UVB sample may have been harvested earlier than the other samples, but this hasn't been confirmed (we will double check with the grower). The third theory is that UVB produces more CBG to the detriment of THCa.

As Prawn was one of the growers involved, I'm sure he will be around to answer any growing questions. Regardless, these tests are not dissimilar to the Or_Gro results, so at least we appear to be seeing a trend with near-UV in the 400-430nm range producing higher THC levels – although in this test there was no LED control without near-UV. For that we would need to harvest samples from a High Red board grown without any supplemental UVB/UVA/near-UV.

 

[Grow Lights Australia]

I know these are not the most scientific tests, but we are trying!

 

[Prawn Connery]

There are a couple of theories on why the UVB sample was so low. The first is that the UVB being on for 12 hours straight was breaking down the THCa faster than the plant was increasing it in response to the added stress. The lab technician had a theory that the UVB sample may have been harvested earlier than the other samples, but this hasn't been confirmed (we will double check with the grower). The third theory is that UVB produces more CBG to the detriment of THCa.

I will check with the grower on when he harvested, but looking at the results, the A Sample had high amounts of decarbed THCa (d9THC), similar to my seven-month old cured sample, so it could be the first theory that UVB breaks down cannabinoids as it stresses the plants to produce more.

EDIT: I just remembered that Sample A was about 2-3 months old as well.

It's worth noting that the 6% UVB 30% UVA Arcadias have a similar UVB:UVA ratio to sunlight, and that having them on 12/12 should produce a similar DLI to sunlight as well. I think there was 96W (4 x 24W bulbs) of UVB fluorescent to about 900W of High Lights in that tent.

 

[PSUAGRO.]

Even in heavy regulated CA, lab results are allowed around ten percent variation/deviation. Some even industry known to boost , not surprising, capitalism. Clients are guilty too, rolling samples in kief/hash oil and shit.

Strict, accurate testing is expensive==== profit negligible with numerous/current batch#'s as required by law.

 

[Prawn Connery]

Sample D
Two High Red Boards, two 315CMH lamps, averaging 1000 PPFD. Coco/perlite run-to-waste, Hygen nutrients. Here is the spectrum.
View attachment 4521013

This sample was from a tent that had 2x 315W CMH and 240W of High Red LEDs (10W per board), so 870W altogether. Here's what the CMH bulb looked like on its own. It's already a nice spectrum, but the High Red board smoothed out the bumps.

 

[Grow Lights Australia]

Even in heavy regulated CA, lab results are allowed around ten percent variation/deviation. Some even industry known to boost , not surprising, capitalism. Clients are guilty too, rolling samples in kief/hash oil and shit.

Strict, accurate testing is expensive==== profit negligible with numerous/current batch#'s as required by law.

Yes it's not cheap I can tell you that! But with this test we wanted to see if there was any noticable difference in the amount of UVB, UVA and near-UV, everything else being fairly equal. You could say the High Red board is the control, as all the tents had similar spectra but with various amounts of UVB + UVA, UVA + near-UV, and near-UV. What we're really trying to see is if we can get the same or similar results with near-UV (400-430nm) compared to the addition of UVB or UVA. So far we see no disadvantage. The next step is to see how it compares to boards that have no UV and no near-UV, which is the majority of LM301B and similar CRI80 based 3030 boards.

 

[wietefras]

Isn't CBG th precursor to other cannabinoids (CBD, CBN and THC)? Perhaps the high CBG samples were harvested prematurely and if left to go longer, more of the CBG would have been converted

 

[end_of_the_tunnel]

Yes it's not cheap I can tell you that! But with this test we wanted to see if there was any noticable difference in the amount of UVB, UVA and near-UV, everything else being fairly equal. You could say the High Red board is the control, as all the tents had similar spectra but with various amounts of UVB + UVA, UVA + near-UV, and near-UV. What we're really trying to see is if we can get the same or similar results with near-UV (400-430nm) compared to the addition of UVB or UVA. So far we see no disadvantage. The next step is to see how it compares to boards that have no UV and no near-UV, which is the majority of LM301B and similar CRI80 based 3030 boards.

Thanks for posting up these results. Something that everyone concerned with improving the quality of meds should consider. Look forward to discussion and results from further examples, including the lower CRI products that are so common in general use.

Follows on nicely from the work by Magagnini, Grassi, Kotiranta.

 

[Grow Lights Australia]

Isn't CBG th precursor to other cannabinoids (CBD, CBN and THC)? Perhaps the high CBG samples were harvested prematurely and if left to go longer, more of the CBG would have been converted

Yes, you are correct. This is probably what the lab technician was saying, as he mentioned it was the precursor to both THCa and CBDa. It appears CBG is at its highest concentration at about six weeks of flowering into an eight-week strain. I have not heard back on whether this sample was harvested early. I'll confirm as soon as I know.

 

[loco41]

Have you guys seen anyone running both the arcadia 6% bulb and the high lights uv board at the same time? Would that be overkill on the uv/near uv to run for a full 12/12 cycle? I was thinking about trying to use the 24 watt t5 fixture with my two boards and just keep the distance a little further at like 20+ inches the whole way though.

 

[Grow Lights Australia]

Have you guys seen anyone running both the arcadia 6% bulb and the high lights uv board at the same time? Would that be overkill on the uv/near uv to run for a full 12/12 cycle? I was thinking about trying to use the 24 watt t5 fixture with my two boards and just keep the distance a little further at like 20+ inches the whole way though.

We haven't had anyone use that configuration yet. But it would definitely give the 400-430nm region a boost. Initially our thoughts were that the reptile bulbs would provide enough UVB/UVA to make a difference without the addition of near-UV. However, after the Or_Gro test samples we learned that we could potentially increase cannabinoids and terpenes with the addition of near-UV alone. We already suspected this from some of the scientific tests we'd read when developing the original High Light UV board, but what surprised us was that the near-UV component of the boards was worth as much as supplementary UVB/UVA.

This latest test appears to support this. What we noted was that the High Red boards with CMH – which have a similar amount of near-UV (but also the addition of UVA) – had results very much in line with the High Light UV boards.

We do believe we are onto something with the addition for 400-430nm diodes to our boards and there now appears to be some evidence to support this. It is unfortunate we cannot do large-scale scientific testing in Australia (at least not yet) so for the time being we very much rely on individal grower tests such as this one and Or_Gro's. We are not saying these tests are infallible, but we do seem to be seeing persistent trends.

 

[Grow Lights Australia]

Isn't CBG th precursor to other cannabinoids (CBD, CBN and THC)? Perhaps the high CBG samples were harvested prematurely and if left to go longer, more of the CBG would have been converted

So we have just had confirmation that the UVB sample provided (Sample A) went full term to eight weeks of flowering and that there is no possibility it was taken early as the gentleman who grew it keeps a grow diary and calendar.

So we're not sure what to make of the results, but we now know they were all eight-week samples. The only variable is that the A sample was a little older (in storage after harvest) than the C and D samples but not as old as the B sample. It is interesting to note that the A and B had the highest d9THC results which reflect the longer storage times prior to testing. This is the reason why we tested the B and C samples from the same grower, as we wanted to also see how the cannabinoid profile changed during the "cure".

 

[Prawn Connery]

I spoke to the grower and he reckons the only other thing that could account for the discrepancy is that the sample bud he supplied was from a lower branch and may not have been fully mature. But I saw the sample (and I smoke tested it!), and it didn't look immature to me.

 

[wietefras]

It could simply mean that the plants under light spectrum "A" needed a while longer to fully ripen.

Perhaps UV slows down ripening a tiny bit.

 

[cobshopgrow]

Cannbioid concentration can differ quite a bit over the plant.
i sadly cant find it anymore, but there was a research paper from israel comparing the impact of growth hormones and how it relates to the distribution of cannabioids in lower and upper buds.
if i remeber correct natural growen plants show a higher concentration in the upper parts.

 

[hybridway2]

According to the lab, as THCa is a precursor to d9THC, the following calculations apply to get the total THC count:

THCa x 0.87 + THC = total d9THC

From this formula we get the following %

Sample A = 16.8% d9THC

Sample B = 24.3% d9THC

Sample C = 22.3% d9THC

Sample D = 21.7% d9THC


Often you will see labs simply combining THCa + THC to get the total d9THC percentage, but apparently this is wrong, as some THCa is lost during decarboxylation (or maybe that is the ratio of THCa conversion to d9THC 100:87).

What is interesting is the UVB sample had the lowest THC levels but almost four times the CBG levels of the other samples. There was not a lot of difference in the other samples, but that is to be expected as two of them (B and C) were grown under the same lights, and the remaining sample (D) was grown under a mix of CMH and High Red that provided similar near-UV and UVA levels (slightly more UVA) .

There are a couple of theories on why the UVB sample was so low. The first is that the UVB being on for 12 hours straight was breaking down the THCa faster than the plant was increasing it in response to the added stress. The lab technician had a theory that the UVB sample may have been harvested earlier than the other samples, but this hasn't been confirmed (we will double check with the grower). The third theory is that UVB produces more CBG to the detriment of THCa.

As Prawn was one of the growers involved, I'm sure he will be around to answer any growing questions. Regardless, these tests are not dissimilar to the Or_Gro results, so at least we appear to be seeing a trend with near-UV in the 400-430nm range producing higher THC levels – although in this test there was no LED control without near-UV. For that we would need to harvest samples from a High Red board grown without any supplemental UVB/UVA/near-UV.

I have read the uvb (even low levels) on all day causes the plant to build a resistance. Defeating the purpose. It probably does in the sun too.
That's one reason why growers use timers & blasts on their UVB.
Glad you guys are doing these tests.
I have often wondered the thc difference between my leds & hps. With the assumption my leds are producing higher levels then the hps by using my senses. I credditted the extra blue or 450+470nm.
Have never been a fan of experimenting much with UVB myself & have always wondered why scientists or grow light companies have always told us the uva is not going to change the thc or other cannabinoids? Why only UVB?
Meanwhile they are not even providing us 400-430, or UVA. And because of the "Scientific Studies" most growers/companies only focused on UVB as their extension to the spectrum at hand.
The tests you are doing shows us this is not true & we do not have to stress or guess our plants with uvb bulbs. Possibly using them wrong.
Many growlight companies are simply going to look past the 400-430 zone & go straight to UVA this yr. For some they are just getting around to n/ir.
But here's the problem with that. As we all know it takes a combo to create the Synergistic Emmerson Effect.
Lack of scientific studies does not explain the Synergistic effects of the other end of the spectrum. They do exist, I'm sure of it.
The whole thing is about balancing this Synergy to me.
You have opened a new realm here by providing test results & running combos.
I mean what other company would toss a cmh in the in the mix if they have the assumption it may outperform the thc #'s of the board alone. And share info.? Not many dude. Granted that is not this past test but you know what i mean.
Kudos to you & your team. That goes for you Prawn.
And thank you!

420 & uva are the only x2 things i wanted added to my existing system for a minute.

Took Balls to attempt & succeeded to make a competitive/efficiency board with Optisolis's.

Curious to the difference between the CMH vs the Highlight board alone. That should indicate whether the less efficient UVA diode is even worth it to some.
I have a feeling the broader spectrum alone might give you darn close to that of the regular white + uva hitting the mkt this yr.

I would be happy to run this test & return or purchase the boards after.
Hmu if interested?
Having other common HE units as well as HPS/MH, we could run tests in parallel. I could sacrifice at least x3, 4.5x4.5 areas to do the test with dividers in the name of science. Oh, we could also test to a light that has 385nm but nothing filling in to 450nm (this yrs new spectrum) That would be the x3 tests at once.
Nothing to do with endorsements of any product by me. I would even keep my opinions to myself n just record.
Simply studies with tests in equal parameters to gain knowledge.

Thanks again for openly sharing your findings repeatedly.

 

[OLD MOTHER SATIVA]

I know these are not the most scientific tests, but we are trying!

you ARE REALLY trying!