UV Light and Terpenoids

VerdantGreen said:

interesting! - i have wondered about this.

would everyone agree that weed grown outside can be more potent and psychoactive than indoor weed?

if its not the spectrum that causes this then what is it? - perhaps longer veg = more mature plants = more potent??

V.

Click to expand...

Most will agree that outdoor bud is at the very least on par with indoor bud, all other things equal (health of plants, consistent feeding, water, etc), and probably more potent.

if it were simply veg time, it should be easily replicatable by growing from clones, no? If not that, then it has to be environmental, and most likely the sun

if it were simply light intensity, this too could be done indoors (inverse square law is our friend), but instead, indoor growers get the degradation of chloroplasts known as light bleaching when they push the intensity.

so it almost has to be spectral in origin. It could be the balance across the spectrum, but this does vary from day to day depending upon the atmospheric conditions, so maybe that could be it?

DocLeaf said:

UV is highest in Spring!

Resin first occurs on underside of leaf blade.

UV has little impact on cannabinoid production.

Click to expand...

the trichomes are a defense mechanism. they could develop on the underside of the leaf to work as an anti-dessicant. that doesnt mean they dont also provide protection from other forms of harm....say, by shielding sensitive cells from UV degradation.

GreenintheThumb said:

But it's been waaaay more than a generation. We've been mostly breeding indoors with low UV light for decades. Has the potency or terpenoids changed? Certainly, but not because of a lack of UV but because of selection. And since our drugtypes are already programed for UV blocking terpenoid/flavinoid/cannabinoids evolutionarily what good comes from adding UV light now? We can already select the best and tastiest without the UV light and the side by side trials seem to show no effect.

Click to expand...

well, that's a road with no direction. Could there have been different phenotypes present today, had we been breeding indoors with the addition of UV light? We dont know for sure.

what we do know is that some good phenotypes have been found without supplementation. Absence of proof is not proof of absence.

But why? Your idea is that UV grown herb would show different phenos than nonUV grown herb which could effect a breeder's decision to cull/keep? But the side by side trials don't seem to support this.


Thanks for everyone's contributions. Looks like it certainly was a ripe topic for discussion.

Click to expand...

StrainBrain's pictures are as illustrative as any Ive seen on the subject.

as someone mentioned earlier, its entirely possible that some strains, or even some individual plants, are more responsive than others. This could account for the mixed opinions on the subject.

the only way to find out if phenotypic expression is effected would be to grow a large number of seedplants (not clones), and see if the trends over a population change. I doubt anyone with the resources to do this has the desire to undergo it.

amoril said:

well, interesting you would make that last question EvilTwin, about UV in veg....

ive been thinking it may be more beneficial in veg than in flowering. to that effect, ive been using it to supplement veg lighting.

my reasoning is, if it does in fact effect the production of terpenes and flavanoids (either through diversification or quantity), then starting this process earlier would yield the most potential benefit.

Click to expand...

I may be following suit on that issue...and since I'm into idioms today: In for a penny...in for a pound.

And another thought I've been mulling over is to elongate the flowering schedule to perhaps 14 hours. With sativas only of course. That would allow more time to administer the UV-B.
Peace,
ET

Strainbrain said:

I've seen firsthand the results from UVB reptile bulbs in my own grow.

The changes it brings about in trichome coverage are visible to the naked eye. The changes that phenomenon brings to the potency are discernable with the head: I've blind-tested it with several friends who were unanimously correct in their assessments. I have not noticed a change in odor, flavor, or character of experience one bit between my three samples - 0%, 2% and 5% UVB lights respectively. Does it change what's in the trichomes? I dunno, seems like it doesn't... but there sure are more of them. (On longer stalks, too.)

To claim it is in any capacity essential, though, is also missing the point. The 0% sample still knocks my socks off, so clearly nobody needs UVB light to grow serious cannabis... but to then conclude that UVB has and furthermore cannot have an effect is simply flawed. You can build a delicious sundae without a cherry on top, but it'd still be better with the cherry. I'll never grow again without UVB.

I'd like to add here that I also see the likelihood that some strains are more- or less-sensitive to UVB. My 'tests' were done with my 'F' clone - of truly unknown genetic origin. It is absolutely sensitive to UVB. If you tested UVB with a strain which is all but insensitive to UVB, however, you'll probably be just as confused by my position as I am by yours... so let's not fling flames or start making wild accusations over this. We might well both be right.


-s

Click to expand...

Got any pics of the UV enhanced buds vs non-UV? Claims are one thing, but until someone does a proper side-by-side grow in controlled conditions and produces meaningful results, I'm highly sceptical.

elmanito said:

@Greeninthethumb
Check it for yourself with this small movie of a grow under a MH plasma light which contains UV a,b,c.This light has the spectra of the sun high in the mountains.The buds look much frostier than under HPS.
The light is 250 watt.No other light is used!!!!

http://www.youtube.com/watch?v=DE6yLuI1NPM

Namaste

Click to expand...

Quartz glass blocks UV, the quartz glass envelopes of MH and HPS bulbs has to block UV under federal and international regulations, otherwise people would suffer from cataracts and others eye and skin complaints, I once tracked down and posted the relevant international standards governing glass envelopes for discharge lighting at another forum, I don't have the info at hand anymore however.

DocLeaf said:

UV is highest in Spring!

Resin first occurs on underside of leaf blade.

UV has little impact on cannabinoid production.

Click to expand...

I disagree on all three of these points. UV is highest in the middle of summer, any quick google of UV level information will show this. Never seen resin form on the undersides of a leaf first, not seen any hard and fast research on this however. 'Little impact' well, define little, are you suggesting it has some impact, albeit little? Hard science needed here, not spurious, random statements.

Perhaps it is best if we all try to stick to researching this subject and tracking down as much published data from reliable sources as we can. Stuff like MJman's video and Joe Knuc's article are worthless, interesting supposition perhaps, but no use at all if we are trying to ascertain hard facts.

EvilTwin said:

I may be following suit on that issue...and since I'm into idioms today: In for a penny...in for a pound.

And another thought I've been mulling over is to elongate the flowering schedule to perhaps 14 hours. With sativas only of course. That would allow more time to administer the UV-B.
Peace,
ET

Click to expand...

you may have it a little backwards....most sativas would be able to vegetate in 14 hours of light. Fairly easily, I would think.

most people report, and my own experience confirms, that with heavy sativas, a shorter photoperiod is sometimes required to get the desired level of flowering. 11/13, 10/14 sometimes. I usually roll in 15 minute increments until I find a sweet spot

indifferent said:

Quartz glass blocks UV, the quartz glass envelopes of MH and HPS bulbs has to block UV under federal and international regulations, otherwise people would suffer from cataracts and others eye and skin complaints, I once tracked down and posted the relevant international standards governing glass envelopes for discharge lighting at another forum, I don't have the info at hand anymore however.

Click to expand...

This light is experimental and has no protection against UV.What you mean about regulations is for public buildings and so on.Wearing normal glasses is just enough to your protect your eyes against UV.

Namaste

But saying that trichomes and cannabinoids are there to block UV light

1) Hasn't ever been proven

2) We're talking about evolution here. Even if trichomes do exist as a shielding agent it doesn't mean at all that applying more UV light will make more trichomes. For instance: maybe eyelashes evolved to keep sand and dirt out of the eyes. Now the way to get more and bigger eyelashes is to breed the folks with the largest eyelashes. The variability exists in the pool and we select towards what we like. Now it wouldn't' really mater if we undertook this in New York or in some sandy ass desert. The variability is there and while it serves an evolutionary function applying that environment (or more of the environment) that sparked this unique trait isn't a concern, what matters is proper breeding and selection.

On the subject of the pictures-
First off thanks for your contribution. They're more convincing than anything i've previously seen. However, don't you think that all sorts of environmental differences could account for the changes in phenotype. What you need to do is grow under you 250 once and then grow under your 250 + supplemental. To me its hard to see a difference between the hps in the first pic and the second pic you posted. Sure the cfl and hps look different but no surprise there.
btw- I've seen your avatar 3 times in real life...i fear it so.

GreenintheThumb said:

But saying that trichomes and cannabinoids are there to block UV light

1) Hasn't ever been proven

2) We're talking about evolution here. Even if trichomes do exist as a shielding agent it doesn't mean at all that applying more UV light will make more trichomes. For instance: maybe eyelashes evolved to keep sand and dirt out of the eyes. Now the way to get more and bigger eyelashes is to breed the folks with the largest eyelashes. The variability exists in the pool and we select towards what we like. Now it wouldn't' really mater if we undertook this in New York or in some sandy ass desert. The variability is there and while it serves an evolutionary function applying that environment (or more of the environment) that sparked this unique trait isn't a concern, what matters is proper breeding and selection.

Click to expand...

thats not quite the point Im getting at.

I linked to a source showing that flavanoids absorb ultraviolet light. flavanoids are phenolic in nature, and as such are permeable through the stalk of the trichome and into the head, from the plant.

the reason the permeate into the CSGT is that they are one of the required reagents in forming the cannabinoids.

So, the theory is that by ensuring this defensive response, by stimulating with UV light, im guaranteeing ample supply of (and possibly some more variation within) the phenol (the component not produced within the trichome) for the cannabinoid synthesis.

even if the variation already exists, it may be possible to stimulate the pathway in plants that would otherwise express it more recessively.

amoril said:

ive been thinking it may be more beneficial in veg than in flowering. to that effect, ive been using it to supplement veg lighting.

my reasoning is, if it does in fact effect the production of terpenes and flavanoids (either through diversification or quantity), then starting this process earlier would yield the most potential benefit.

Click to expand...

I agree with you that it makes sense to start treatment in veg. I haven't done enough 'testing' - I say that as if I'm in a lab and not my bedroom closet - but I did have occasion to veg in my CFL box (2%) a couple of months ago as cycles and space ebbed and flowed in my grow. Some plants spent about 2 weeks under those light conditions, and all of them were strains I'd grown before. They have been flowered - and didn't show any increase in trichome density or in fact any other effects. Those were the last plants to be flowered without some UV present.

My working hypothesis is that it is functioning much like, say, a PK boost. Just as the PK won't really help you build fat buds if you give it in week 4 of veg, the UVB seems to have little or no effect on trich development when the plant's not making trichs. Two reasons I think this:

1) Plants vegged under UVB - including 3 of my mothers - seemed unaffected. When flowered without UVB in my tent they made resin consistent with such conditions. I won't be able to properly judge the clones from those moms as I now have UVB in both flowering chambers.

2) Plants receiving UVB for only the final weeks of flowering show what appears to be the full benefit of the treatment. My 5% sample had only 4 weeks of UVB at the end (out of 8 total) and turned out superior to the 2% sample, which had its UVB present from day 1. I haven't tried 5% from day 1, so I cannot say that for certain.

Don't let this stop you, I haven't really applied even minimal scientific-process to the veg angle. I'd be very interested in your conclusions, if you see it through.

Beyond using it as a selection aid by highlighting phenos with UVB-sensitivity, though, I am not sure what role it can play in breeding. It might even be counterproductive in the indoor industry as few of us use UVB light in our gardens. A plant which slightly outperforms her sisters under UVB might - assuming sensitivity is a variable trait - slightly underperform without it and therefore be inferior in 95% of gardens. I'm venturing beyond my expertise with such suppositions. I just know that it can have a positive impact on the quality of the finished product and it can therefore be of use to the 'end-user,' no matter what it is to the breeder. I have proven this to my own full satisfaction.

And to the question of application period... I run mine for the full 12/12 cycle. I have not experienced undue stress from the UV light - in fact, a C99 fan leaf tip grew up into the center of the bulb last week and was dark green and happy as could be, even while physically touching the glass.


-s

amoril said:

you may have it a little backwards....most sativas would be able to vegetate in 14 hours of light. Fairly easily, I would think.

most people report, and my own experience confirms, that with heavy sativas, a shorter photoperiod is sometimes required to get the desired level of flowering. 11/13, 10/14 sometimes. I usually roll in 15 minute increments until I find a sweet spot

Click to expand...

Leave it to me to get that backwards. Always just used 12/12 but have read that variations are possible, especially with sats. Back to the books.

And on the safety issue...
My lights simulate full sun UV-B at 3'-4' feet (they're mercury vapor) so it is possible to get dangerous doses by being exposed at closer distances.

So just to be on the safe side, I installed a door switch so I can't enter the room with the UV lights on. Easy enough and a reasonable precaution. Don't want to mess with my health.
Peace,
ET

GreenintheThumb said:

First off thanks for your contribution. They're more convincing than anything i've previously seen. However, don't you think that all sorts of environmental differences could account for the changes in phenotype. What you need to do is grow under you 250 once and then grow under your 250 + supplemental. To me its hard to see a difference between the hps in the first pic and the second pic you posted. Sure the cfl and hps look different but no surprise there.

Click to expand...

No thanks necessary, I'm happy to contribute anything which may help us grow better.

The '0%' sample and the '5%' sample are exactly what you mention - grown under the 250 alone, and then the 250 + UVB. The trichome levels are night and day. It is only the 2% sample which comes from the other chamber.

For the record... the two environments are virtually identical in most respects. Temperatures are consistently within 2-3F of one another and light level - at least measured in initial-lumens of the bulbs per square foot - is all but identical. (One is at 7000 and one at 7250.)

I grow with the same medium and same nutes in both.

The CFL box has more blue-spectrum light, which remains a variable.

btw- I've seen your avatar 3 times in real life...i fear it so.

Click to expand...

Ouch... I'm sorry to hear that. Damned machines... I don't even own one.


-s

Sure, the sun has UV light, while it is lacking in the usual indoor growing lamps. That's ok.

As far as the UV levels at higher altitudes, such as the tops of mountains, that's kind of useless information. You just don't find cannabis growing on mountain tops, and not so often above 5000 ft elevation... besides:

"Wild growing Cannabis from different altitudes and locations was collected in northern India. Plant material from each collection was analyzed quantitatively for ten cannabinoids by GC. The average total cannabinoid content of plants growing above 2,000 m was 1.33 %, whereas below 2,000 m the average total cannabinoid content was 2.74 %. Morphological characteristics were recorded. Data obtained from wild growing Indian Cannabis (twenty variants) are compared with data obtained from the same variants grown in Mississippi, USA."

Abstract from "Constituents of Cannabis sativa
XV: Botanical and Chemical Profile of Indian Variants"
Planta Med 1979; 37: 217-225

BTW, I absolutely HATE at least one of the researchers of that paper.

guys, i didnt want to send this off topic but i have a related question and your expertise may facilitate the answer

http://icmag.com/ic/showthread.php?t=140101

thanks

V.

You can find cannabis above 5000 ft more often than you think.What do you think of Himachal Pradesh (Kulu Manali, Parvati).
Here is some other research about this subject.

http://www.springerlink.com/content/q450642638287947/

http://www.hempfood.com/Iha/iha01201.html

Namaste

I'd say that the Pate paper describes a "possible" alternative route of cannabinoid production in some plants which may have "possibly" been growing in areas of higher UV light. This means that UV light will have no beneficial effect whatsoever on cannabis which would not have had the "possibility" of growing in high altitude conditions, since they would never have been forced to adapt in this way.

Most of Pradesh where the weed would grow is under 5000 ft. No one is risking their lives hiking miles up to get whatever scraggly little shrub form might grow there.

*mr.mike* said:

I'd say that the Pate paper describes a "possible" alternative route of cannabinoid production in some plants which may have "possibly" been growing in areas of higher UV light. This means that UV light will have no beneficial effect whatsoever on cannabis which would not have had the "possibility" of growing in high altitude conditions, since they would never have been forced to adapt in this way.

Most of Pradesh where the weed would grow is under 5000 ft. No one is risking their lives hiking miles up to get whatever scraggly little shrub form might grow there.

Click to expand...

That paper from Pate is from 1983 and today we know a little bit more about this.There are some varieties which have adapted to higher altitude with a higher UV-concentration by higher THC-production.Highland Thai e.g. is famous for its potency and clearless high effect.Dont forget the North Indian and Nepali strains.

Kullu Manali where one of the great varieties is coming from is at 6260 ft and not below 5000 ft.

Namaste

I've always wanted to try a test run with a few UV-B bulbs in my grow room. I do believe that it would be beneficial to the plants, how much and in what way I don't know but I will have to try it soon, whats up with them plasma lights? Anyone got any more info on em?
HGO

Happy Halloween All, toker,treat!

you want to test this theory????

Anyone have a rectangular, 3x6 or 4x8 E&F tray... 2 lamps split the tray down the middle with B/W Poly..

Monocrop the tray and add UV-b to one side. You'd know they were getting same feed regimen this way and very easily be able to compare results. My trays are too small for 2 lamps or I'd give it a shot.

Come back and share results

Oo, BTW, I believe blazeoneup uses UV-B bulbs in his flower room if I remember correctly..