[Green_science]

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]

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

[Evocho]

?

[ZZTops]

What Side...?

[nuskool89]

I am going to go out on a limb and say the UV won't produce any noticeable difference.

[applepoop911]

maybe not during veg but there have been alot fo studies il post one when i can find it

[k-grower]

https://onlinelibrary.wiley.com/doi/1...757.x/abstract

there is the article

[the gnome]

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

Originally Posted by nuskool89

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]

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.

kind regards from guineapig

[BagAppeal]

What type of UV light are you using?
Tropical, desert? 5.0 - 10.0
All the best
BagAppeal