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UVB VS NO UVB Side by Side

Green_science

Active member
This will be a well controlled experiment to test the difference between plants grown with UVB supplementation, and plants grown without.

The genetics are a strain called "psycho berry", they are all clones taken from the same mother.
They are running in NFT, in a 3x1.5m space, each side of the space has a single spectrum 1kw purely red bulb, there is a dual spectrum 600w hanging vertically in the center (but this is just to increase yield and contains little to no UVB.

Environmental factors
are rather equal and symmetrical throughout, temp and humidity range positives over the entire canopy are minimal to none.

The test done by some scientist, that some of you will no doubt refer to in this thread, is somewhat lacking in or rather has some misconceiving info in regards to amount of uvb supplemented (it seems RATHER low)

I am sure we will mostly agree that geographically the Hindu Kush is probably responsible for harboring the strongest land-races known to nature, so lets work down from here.

A good estimate for watts per square meter of sun power, along side these valleys/mountains, would be around 1050 watts.

If we take the fact that at ground level 3% of the suns power is composed of UV, this gives us around 31.5 watts per meter squared of "UV"

UV levels increase by 4% for every 300 metre rise in altitude, and the Valley of Kuran wa Munjan, is situated 1,800m above sea level, so lets take our 31.5 watts and increase it by %24 (7.5 watts) this gives us around about 39 watts per meter squared of UV radiation in the Hindu Kush ( and I think that's being generous)

Our ozone is great of coarse at filtering UVB (and the more energetic wavelengths), however we are not at great enough elevation in the Hindu Kush to start factoring this in.

Now lets consider that UVB rays constitute only 5% of ultraviolet radiation in our ozone and this gives us 5% of 39 watts, (1.95) to make it simple lets say that, in the Hindu kush UVB radiation is around 2 watts per square meter.

Our space is 1.5 x 1.5 meters which = 2.25 m2, so 2 watts(per square meter) x 2.25(meters squared) = 4.5 watts of UVB (AT CANOPY LEVEL) needed for our test

Now lets consider that "Repti Glo 10.0" bulbs are 10% UVB (290 to 320 nm), we would need 45 watts of this particular bulb, this is of coarse not factoring in loss of irradiance (meaning these bulbs will not be touching the test canopy(inverse square law)).

If we do factor in the above and consider the distance light source will be from canopy, we are going to want much closer to 80 watts of said bulb, which is great anyway because they are available in 40 watt tube models.

Lighting schedule: UV is at its peak during solar noon, and is dramatically lower in the mornings and evenings, IMHO, I think giving test plants 4 hours of UVB supplementation either side of their solar noon, (8 hours per day in total) is a pretty good compromise and quiet accurately replicates nature, if anyone disagrees with this please let me know.

When I started this thread it was not made active for a few weeks and I did not think it was going to be made active so I did not bother setting up the test, the plants are now 3 weeks into 12/12 so it's still early enough to setup, I will get on the case immediately, for those, including myself, that are very interested in an accurate comparison of UVB.

Testing Results: I do not currently have access to a Gas Chromatography test to compare the 2 samples, if someone wants to help out here let me know, I can provide the funds.
Of coarse if a obvious visual difference is noticeable then the test will provide a positive answer, HOWEVER if a visual difference is not noticeable we could still be missing something that a GC will detect, and even if a visual difference is noticeable I am sure we all want to know in percentage values what kind of increases took place, like I said someone reach out to me.

Conclusion to introduction:To properly replicate UVB levels in the Hindu Kush (where some of the most potent cannabis grows naturally) in to our test environment (or more accurately, test plants canopy) , we are going to want to use around 80 watts of "Repti Glo 10.0" bulbs. UVB supplementation will be timed to accurately represent concentration levels of UVB in said geographic region, we will look for a visual difference, a difference in affects during consumption, and hopefully a accurate test showing us the definitive answer to our test

Here are a few pics of our test area, I will take some more as soon as I get UVB equipment running







---------------------------IMPORTANT EDIT----------------------
After being prompted by a forum member to research the quality of the Repti Glo bulbs, it seems they have some problems keeping a reasonable level of UVB concentration over short distances, upon his recommendation and some quick research it seems the best form of UVB supplementation for this experiment is going to come in the form of "Arcadia D3+ T-5 46 Inch 54 Watt *12% Desert UVB" lamps, which will now be taking place of the Repti Glo's!
 

Green_science

Active member
UVB VS NO UVB Side by Side

I cannot seem to find any side by side threads anywhere, documenting the effects of uvb supplementation so decided to start this one here.

The test environment will have a dimension of 3m x 1.5m, one side will receive UVB supplementation the other will not.

All plants are clones from the same parent, grown hydroponically receiving the same feedings.
The environmental variable maximums are 2 degrees fahrenheit and 5% relative humidity at its furthest points, this is when transitioning from night/day, and most of the time has even smaller positives.

UVB supplementation will come in the form of check edit in previous post, and will be setup as shown in the diagram below.

(we will only be paying attention to test subjects within test areas a and b, to extend the accuracy of the experiment)




Once our main lights are flipped over to a schedule of 12/12, UVB will be supplemented straight away, for 6 hours per day, 3 hours either side of the plants solar noon.

Our main lighting being used will come in the form of 2 x 1kw Osram Son T HPS bulbs, these output very little blue and far blue wavelengths which make them perfect for this test.

After harvest I will try to arrange a full gas chromatography test on samples from each of the test areas (if anyone can help with this PM me)

To put this in to context this test will be VERY accurate and will finally give us some real world data on weather or not UVB supplementation on indoor cannabis plants actually has an affect on the final produce.

The plants have only been vegging in the NFT system for a couple weeks and I will not be inducing the blooming phase for another few weeks, so if like me you are interested in this topic, sub this thread and check back in a few weeks.

In the mean time I am open to discussion and am happy to answer any questions you may have, below I will attach a few photos of the test subjects and environment


 

the gnome

Active member
Veteran
GS, can you give any more info on the controls etc etc
your using for the comparisons?


I am going to go out on a limb and say the UV won't produce any noticeable difference.
I'm leaning that way myself but what I'm thinking is the genetics side of it may show certain strains may react to uvb more or less than other strains?
 

guineapig

Active member
Veteran
In the book Cannabis Botany, Robert Connell Clarke references an experiment from
the laboratory of Dr. Melchoulam, one of the leading cannabinoid researchers.
In that experiment, CBN was converted to THC simply by exposure to UV-B light
I believe it was 45% conversion rate, and also the researchers found small
amounts of very rare cannabinoid variations not commonly detected in natural cannabis.

I am sure we could find that quote in RCC's book. I have quoted it here in the past when
the subject of UV light comes up every now and then. Also, there is a paper called
"Marijuana Optics" that talks about how the resin sphere is basically a light collection
device that concentrates light into the cannabinoids. The author goes into detail about
UV-B light and how it is important for creating a "fully realized" cannabinoid profile.
I haven't seen that paper in awhile, maybe it is still around. I think a Canadian cannabis
researcher wrote that paper, name redacted.

:ying: kind regards from guineapig :ying:
 

Green_science

Active member
Hey everyone,thread updated and welcome, I think all of you're Q.'s have been answered in my updated post, let me know if there's anything else

GS
 

Sam_Skunkman

"RESIN BREEDER"
Moderator
Veteran
What happened to Green science? Please run the test and analyze the results and post them!!
I ran a test a bit like this 20 years ago.
I had several different clones of high THC varieties, and industrial hemp, and a wild cannabis variety from the mountains.
I placed each clone in rows of five so they had a chance to be exposed to too high of levels, medium, and low levels, depending on the distance from the light sources.
To cut to the chase, no increase compared to controls without UV-B.
In fact the plants closest to the lights were a bit zapped and had lower plant weights and lower Cannabinoid levels.
(In my own opinion using organic soils to increase root mass, which gives Cannabis with improved terpene yield and better Cannabis yield is much better then UV-B supplement.)

Tonygreen,
As for On page 31 if you scroll down you get into some good stuff and an interesting hypothesis about thc. They quote Lydon and Pate, but Pate did my experiments with me
setting them up and measuring the UV-B levels, as well as testing the results on our GC.
He was unable to increase the THC levels. Lydon thinks CBD can be converted to THC, but most Cannabis grown in the west has no CBD to start with. Lydon also only dosed the plants with UV-B for only 40 days, part of those when the plant was still in veg. He also said no increase in THC in hemp plants so I guess CBD does not get converted to THC by UVB?
We tried several times, zero THC increase. I have never seen any lab results that showed an increase in THC from UVB exposure, I have never seen Lydon's work replicated, except when I tried but got no increase in THC.
As for "Marijuana Optics" anyone that reads it and thinks it is science needs to stop smoking so much.
Get all three of Lydon's papers and try to repeat the work, if I remember correctly he did not even use clones for the work, for sure in the case of Lydon's 1985 Thesis, I think the 1987 paper also. I will go find the papers and re-read them....

-SamS
 
Last edited:

k-grower

Member
What happened to Green science? Please run the test and analyze the results and post them!!
I ran a test a bit like this 20 years ago.
I had several different clones of high THC varieties, and industrial hemp, and a wild cannabis variety from the mountains.
I placed each clone in rows of five so they had a chance to be exposed to too high of levels, medium, and low levels, depending on the distance from the light sources.
To cut to the chase, no increase compared to controls without UV-B.
In fact the plants closest to the lights were a bit zapped and had lower plant weights and lower Cannabinoid levels.
(In my own opinion using organic soils to increase root mass, which gives Cannabis with improved terpene yield and better Cannabis yield is much better then UV-B supplement.)

Tonygreen,
As for On page 31 if you scroll down you get into some good stuff and an interesting hypothesis about thc. They quote Lydon and Pate, but Pate did my experiments with me
setting them up and measuring the UV-B levels, as well as testing the results on our GC.
He was unable to increase the THC levels. Lydon thinks CBD can be converted to THC, but most Cannabis grown in the west has no CBD to start with. Lydon also only dosed the plants with UV-B for only 40 days, part of those when the plant was still in veg. He also said no increase in THC in hemp plants so I guess CBD does not get converted to THC by UVB?
We tried several times, zero THC increase. I have never seen any lab results that showed an increase in THC from UVB exposure, I have never seen Lydon's work replicated, except when I tried but got no increase in THC.
As for "Marijuana Optics" anyone that reads it and thinks it is science needs to stop smoking so much.
Get all three of Lydon's papers and try to repeat the work, if I remember correctly he did not even use clones for the work. Maybe I am mixed up? I will go find the papers and re-read them....

-SamS

it is all depended on genetics of the plant, just make account here and read the science study of uv-b
http://onlinelibrary.wiley.com/doi/10.1111/j.1751-1097.1987.tb04757.x/abstract

from the study -

"The effects of UV-B radiation on photosynthesis, growth and cannabinoid production of two greenhouse-grown C. sativa chemotypes (drug and fiber) were assessed. Terminal meristems of vegetative and reproductive tissues were irradiated for 40 days at a daily dose of 0, 6.7 or 13.4 kJ m-2 biologically effective UV-B radiation. Infrared gas analysis was used to measure the physiological response of mature leaves, whereas gas-liquid chromatography was used to determine the concentration of cannabinoids in leaf and floral tissue.

There were no significant physiological or morphological differences among UV-B treatments in either drug- or fiber-type plants. The concentration of Δ9-tetrahydrocannabinol (Δ9-THC), but not of other cannabinoids, in both leaf and floral tissues increased with UV-B dose in drug-type plants. None of the cannabinoids in fiber-type plants were affected by UV-B radiation.

The increased levels of Δ9-THC in leaves after irradiation may account for the physiological and morphological tolerance to UV-B radiation in the drug-type plants. However, fiber plants showed no comparable change in the level of cannabidiol (a cannabinoid with UV-B absorptive characteristics similar to Δ9 THC). Thus the contribution of cannabinoids as selective UV-B filters in C. sativa is equivocal."
 

Green_science

Active member
@Sam_Skunkman, Sorry my friend there was some confusion on my part with this thread, I do not know when or how post#2 appeared and can be deleted, I did not think this thread was going to make it, until I just see it was eventually permitted and made active by you guys.

I have ordered the parts and they should be here and setup for Friday, I purposefully ordered a ballast that has a dimmer feature that gently powers the bulbs on and off, to replicate Dusk/Dawn, this feature takes 30 minutes each side,
The ballast which has a built in timer has a minimum day length of 10 hours which is okay, once we minus the hour for soft start/stop feature it equates to 9 hours of full power UVB supplementation per day, PERHAPS a little much, but I really cannot see it hindering this test.

I will report back when things are setup and running, this will be at latest Monday, in the meanwhile if anyone has any request let me know?
 

Sam_Skunkman

"RESIN BREEDER"
Moderator
Veteran
Great! Be sure you have control plants grown exactly the same with no UV-B, as well as a lab that will test for the Cannabinoids as well as the terpenes. Good luck, I really would like to see the results analyzed for yield, Cannabinoids as well as preference by smokers. The reason I did the work was because I wanted to see if UV-B could help, I just could not prove it did.
-SamS


@Sam_Skunkman, Sorry my friend there was some confusion on my part with this thread, I do not know when or how post#2 appeared and can be deleted, I did not think this thread was going to make it, until I just see it was eventually permitted and made active by you guys.

I have ordered the parts and they should be here and setup for Friday, I purposefully ordered a ballast that has a dimmer feature that gently powers the bulbs on and off, to replicate Dusk/Dawn, this feature takes 30 minutes each side,
The ballast which has a built in timer has a minimum day length of 10 hours which is okay, once we minus the hour for soft start/stop feature it equates to 9 hours of full power UVB supplementation per day, PERHAPS a little much, but I really cannot see it hindering this test.

I will report back when things are setup and running, this will be at latest Monday, in the meanwhile if anyone has any request let me know?
 

Green_science

Active member
Great! Be sure you have control plants grown exactly the same with no UV-B, as well as a lab that will test for the Cannabinoids as well as the terpenes. Good luck, I really would like to see the results analyzed for yield, Cannabinoids as well as preference by smokers. The reason I did the work was because I wanted to see if UV-B could help, I just could not prove it did.
-SamS

Sure thing, the control sets are in the same NFT tray drinking the same feed in the same environment, also they are genetic clones. For testing purposes produce used will come from opposite sides, one side will be receiving near NILL UVB whilst the other will be supplemented with levels (at least similar) to that in the Hindu Kush valleys, of coarse we aren't in lab conditions but the differentials other than the one we are testing are MINIMAL I assure you, so it is safe to say this test is pretty darn accurate.

I have run a few ops supplemented with UVB. VVVVVVVVV

picture.php


In the above instance something that I would consider unusual happened, it seemed that leaves around the UVB bulbs yellowed early, and, much more than usual, and whilst using my usual methods.

The strain in question was one I am not familiar with however, so perhaps I just couldn't dial it in, pretty unlikely tbh.

I am uncertain of the results, but it seemed, and I say it cautiously, that the uvb supplementation was possibly responsible for accelerated maturation without compromising yield, sure I was unfamiliar with the strain, but you can almost see it in the pic, the plants that had an abundunce of UVB, seemed more ripe and larger, before others with less access to UVB, this definitely wouldn't be the case if the fact were simply light bleaching, heat burn or a deficiency. None of this is concrete and I am not even sure if I believe it myself, however the test in this thread is going to be quiet accurate, so, the million doller question will be answered within the next 2 months. I do not sell UVB lights, I do not own any shares in any party's that sell UVB lights, I have nothing to gain from promoting the use of UVB lights etc etc, so you can all have plenty of faith in this being a honest, fair and unbiased test that I will perform as accurately as possible with no ulterior motives involved, it's simply to further extend our knowledge
 
Just wanted to chim in real quickly that if you are using repti-glo uvb lights they suck compared to the better UVB bulbs on the market. All tests on those bulbs have shown without the correct glass(Quartz glass) to transmit UVB, very little result will come from these junk bulbs. Want proof? Here you go measuring light output with a meter.

See what Dr Baines has to say.

http://www.youtube.com/watch?v=AUu24MNO2Ho


....and if you are not familiar with her, please google her and please visit her web-site.

She is the top expert on UV and advises Zoos all over the world.

And she does independent testing for Arcadia, Zoo med and Lucky Reptile (german) among many others...

She does NOT endorse any products...

but you can see what ones she presents in her demonstrations.

They only ones worth purchasing are the Zoo med Reptisun UVB 10 and the Best 12% HO UVB bulbs from Arcadia. Arcadia D3+ T-5 46 Inch 54 Watt *12% Desert UVB is right now the best ones to use. They also have Mercury Vapor lamps in 160 watt spot bulbs HO UVB lights.
Any tests done using any other bulbs will show little difference because, "You are not doing it right."

Last here is a picture of UVB lights over a nice little crop. Only thing I will change is the distance between the lights and the plants. Will try and get it as close as possible to the plants.
Pictured is 4 36 watt Reptisun UVB 10 bulbs and 2 96 watt HO 7% UVB bulbs. Not available anymore. At least they are HO Bulbs.


 

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One last thing, You will need to move(rotate) the plants around to get the best exposure to the UVB light. I turn the plants every 3 days when watering so a different side gets exposed to that light source.

I used to work with Zoo Med years ago and is how I learned about UVB lights and what makes one better than the others.
Hope that helps.
 
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