PSA: UV-B bullsh*t

[CannaT]

Plant can grow without UV but plant with UV will be always better quality.

If for example plants grow in same nutrient solution,same room temp,setup and only difference is with or without UV im shure plant will be better with UV.

Coca can be grown probably everywhere in greenhouses...but it can never have high procent of 1-1.5% in leafs like when its grown on high additudes like it does in some part of south america.

Everything on this world is poison,dosage is what makes the cure.

Shure plants will benefit more with uv than without if you give the right dosage to them.

 

[Verdant Whisperer]

i think the question now, is what uv complex (mix of uv's) is most efficient and what intensity match of uv matches the light intensity, to find the optimum ratio for plant health, where its using 100% of light and getting benefits of UV. If the UV is too strong the plant won't get close enough to light to get maximum Par, but if the UV is too weak it won't do much. so, finding that sweet spot would be ideal.

 

[CannaT]

i think the question now, is what uv complex (mix of uv's) is most efficient and what intensity match of uv matches the light intensity, to find the optimum ratio for plant health, where its using 100% of light and getting benefits of UV. If the UV is too strong the plant won't get close enough to light to get maximum Par, but if the UV is too weak it won't do much. so, finding that sweet spot would be ideal.

Everything in life must compensate ,whatever you do you begin with the sam amount of mass.
Mass is like enerygie it cant be lost.

 

[Rocket Soul]

i think the question now, is what uv complex (mix of uv's) is most efficient and what intensity match of uv matches the light intensity, to find the optimum ratio for plant health, where its using 100% of light and getting benefits of UV. If the UV is too strong the plant won't get close enough to light to get maximum Par, but if the UV is too weak it won't do much. so, finding that sweet spot would be ideal.

UV as a percentage is about 3-6% of sunlight depending on altitude. Obviously, since sunlight is much stronger than any indoor light those 3-6% is a lot more in absolute terms.
For my own designs i try to make sure i can add about 10% of total wattage as UV and far red, without driving diodes too hard and using relatively decent diodes.

As far as diodes/nm:
UVA/N-UVA:
400nm : generally quite efficient diodes in this range and its also highly photosynthetically efficient. I use it more like a blue filler
365nm: seems to be the most reactive part of the uva spectrum, it has a large bump in its stomata apperture actionspectrum. My guess is that nature mostly recycles, and that this nm would also have the most effect on other uv related parts of plant fisiology. But hey, only guessing here.
UVB:
Currently running 295nm, but i would like to try adding 285nm (peak uvr8 response without too much uvc) and 300nm (ive seen it mentioned as peak response of HY5 gene response which is also part of the uvb response).

One thing to mention is that ive seen small scale tests where just near uva in generous amounts beat out uva+uvb in potency. Uvb seems to both stimulate cannabinoid aswell as breaking it down. Getting the balance right is the main thing. As for intensities id go blue>N-UVA>UVA>UVB, following the sunlight spectrum.

 

[Ca++]

Your rig talk, suggests 0.1w of UVB per meter.
I was using 3w, or 30x more. I also had that much UVA, in order to balance it up, in respect of my PAR ppfd.
This means your experiment differs from the usual UV papers that most of us are thinking of, when UV talks come up. Your looking at something like far blue, which has the more accurate term of near UV. With next to no actual UV at all.

Perhaps you could dangle a UV-B lamp in one corner next time. Then you can see the range of effects, from right by the lamp where you have a lot of radiation, and how any observed effect lessens as you move from the lamp. This offers a much greater range of results, as you have different levels of radiation, across the space.


We could grow green leather with mercury vapour lamps

Many thousands of growers played around with the ratio of mercury lamps to sodium lamps for bloom. Initially people wouldn't let go, and simply added a HPS beside there mercury. Over time though, people dropped the mercury. This is before the internet, and before most people had read a single word about spectrum. When the only goal was to grow the best gear. The metal halide reduced the UV further, and was the better lamp. Though it produces fair amounts of UVB, likely more than you are using. This is why the UV crew of the 90s would suggest a halide to hps ratio of 1:4 quite often. That was when I first started UV testing in a way, although I only think of it now. I had 150w MH lamps I would dot about in corners if they were lacking. Judged beside sodium, the buds were smaller, but a bit denser. More green colour and that expected toughness to them. The resin production looked higher, but was more of an optical illusion. Obviously we raced to try it, but meh.

I once swapped to MH for the last two weeks, and it was one of the daftest things I have done. I was willing to try it though, to finally bury the idea. Again, it's not one of the UV runs I use in my decision making. Though it seems I have tried UV a few times more than I care to remember.

We get a lot of niche lighting brands target us, with anything they think we will buy. We also get a lot of people, like myself, with personal views. When I want to confirm my findings, I look to my peers that took that route as a full time profession. Here, I'm listening to Philips and Osram. We may not of ever seen a Philips grow light, but that's because we are mushrooms. Philips light more crops than anyone else. Spending vast amounts on research to take that number one position. Osram are right up there to, but trade under a different brand for us. Fluence. Another giant in plant lighting, that has looked at UV application and decided not to.
I'm satisfied by finding the industry giants agree with me. A feeling compounded by the papers I read, from leading figures in cannabis research. Then for the finishing touch of satisfaction, I see the thoughts of my peers here. Often expressed as their unwillingness to get involved.
I'm not blinkered though. If there are any papers to support UV use with cannabis, I ask again to see them. Anything else is just background noise.

 

[CannaT]

Your rig talk, suggests 0.1w of UVB per meter.
I was using 3w, or 30x more. I also had that much UVA, in order to balance it up, in respect of my PAR ppfd.
This means your experiment differs from the usual UV papers that most of us are thinking of, when UV talks come up. Your looking at something like far blue, which has the more accurate term of near UV. With next to no actual UV at all.

Perhaps you could dangle a UV-B lamp in one corner next time. Then you can see the range of effects, from right by the lamp where you have a lot of radiation, and how any observed effect lessens as you move from the lamp. This offers a much greater range of results, as you have different levels of radiation, across the space.


We could grow green leather with mercury vapour lamps

Many thousands of growers played around with the ratio of mercury lamps to sodium lamps for bloom. Initially people wouldn't let go, and simply added a HPS beside there mercury. Over time though, people dropped the mercury. This is before the internet, and before most people had read a single word about spectrum. When the only goal was to grow the best gear. The metal halide reduced the UV further, and was the better lamp. Though it produces fair amounts of UVB, likely more than you are using. This is why the UV crew of the 90s would suggest a halide to hps ratio of 1:4 quite often. That was when I first started UV testing in a way, although I only think of it now. I had 150w MH lamps I would dot about in corners if they were lacking. Judged beside sodium, the buds were smaller, but a bit denser. More green colour and that expected toughness to them. The resin production looked higher, but was more of an optical illusion. Obviously we raced to try it, but meh.

I once swapped to MH for the last two weeks, and it was one of the daftest things I have done. I was willing to try it though, to finally bury the idea. Again, it's not one of the UV runs I use in my decision making. Though it seems I have tried UV a few times more than I care to remember.

We get a lot of niche lighting brands target us, with anything they think we will buy. We also get a lot of people, like myself, with personal views. When I want to confirm my findings, I look to my peers that took that route as a full time profession. Here, I'm listening to Philips and Osram. We may not of ever seen a Philips grow light, but that's because we are mushrooms. Philips light more crops than anyone else. Spending vast amounts on research to take that number one position. Osram are right up there to, but trade under a different brand for us. Fluence. Another giant in plant lighting, that has looked at UV application and decided not to.
I'm satisfied by finding the industry giants agree with me. A feeling compounded by the papers I read, from leading figures in cannabis research. Then for the finishing touch of satisfaction, I see the thoughts of my peers here. Often expressed as their unwillingness to get involved.
I'm not blinkered though. If there are any papers to support UV use with cannabis, I ask again to see them. Anything else is just background noise.

Your knowladge seems big...but what your plants say.
Do you have some pictures of your grow.

Everything works in theory, but practice is something else.

 

[Ca++]

Why would you want to look at my grow, when you can look at the work of industry champions, who would like nothing better than to sell you more lighting products. My grow is insignificant, beside the volume of peer reviewed papers available on the subject.


I'm really waiting for some papers that say it's good, Or I'm just stood here wasting my time. I have some lamps I should be changing before work..

 

[Rocket Soul]

Your rig talk, suggests 0.1w of UVB per meter.
I was using 3w, or 30x more. I also had that much UVA, in order to balance it up, in respect of my PAR ppfd.
This means your experiment differs from the usual UV papers that most of us are thinking of, when UV talks come up. Your looking at something like far blue, which has the more accurate term of near UV. With next to no actual UV at all.

Perhaps you could dangle a UV-B lamp in one corner next time. Then you can see the range of effects, from right by the lamp where you have a lot of radiation, and how any observed effect lessens as you move from the lamp. This offers a much greater range of results, as you have different levels of radiation, across the space.


We could grow green leather with mercury vapour lamps

Many thousands of growers played around with the ratio of mercury lamps to sodium lamps for bloom. Initially people wouldn't let go, and simply added a HPS beside there mercury. Over time though, people dropped the mercury. This is before the internet, and before most people had read a single word about spectrum. When the only goal was to grow the best gear. The metal halide reduced the UV further, and was the better lamp. Though it produces fair amounts of UVB, likely more than you are using. This is why the UV crew of the 90s would suggest a halide to hps ratio of 1:4 quite often. That was when I first started UV testing in a way, although I only think of it now. I had 150w MH lamps I would dot about in corners if they were lacking. Judged beside sodium, the buds were smaller, but a bit denser. More green colour and that expected toughness to them. The resin production looked higher, but was more of an optical illusion. Obviously we raced to try it, but meh.

I once swapped to MH for the last two weeks, and it was one of the daftest things I have done. I was willing to try it though, to finally bury the idea. Again, it's not one of the UV runs I use in my decision making. Though it seems I have tried UV a few times more than I care to remember.

We get a lot of niche lighting brands target us, with anything they think we will buy. We also get a lot of people, like myself, with personal views. When I want to confirm my findings, I look to my peers that took that route as a full time profession. Here, I'm listening to Philips and Osram. We may not of ever seen a Philips grow light, but that's because we are mushrooms. Philips light more crops than anyone else. Spending vast amounts on research to take that number one position. Osram are right up there to, but trade under a different brand for us. Fluence. Another giant in plant lighting, that has looked at UV application and decided not to.
I'm satisfied by finding the industry giants agree with me. A feeling compounded by the papers I read, from leading figures in cannabis research. Then for the finishing touch of satisfaction, I see the thoughts of my peers here. Often expressed as their unwillingness to get involved.
I'm not blinkered though. If there are any papers to support UV use with cannabis, I ask again to see them. Anything else is just background noise.

Thank you for providing details.
3w of uvb output is a lot, even if the spectrum you supplied suggest it isnt directly targeting the UVR8 gene action spectrum. How much uva were you using?

Have you considered whether the reason for not getting your desired results were down to using too much uvb?

Far Blue? You mean violet?
The rig im using for tests is uva 400/365nm at 1:1 ratio.

 

[led05]

Yup because lots of people buy worse than useless UV lights, that UV damages their plants' DNA and reduces plant growth without benefit in most cases. Plus UV typically has a negative effect on terpenes and other secondary metabolites (what you call "ingredients") as the terpene profile of UV control plants is not simply increased across the board, many terps we want are reduced and some we don't want are increased.

And the rest of your message has nothing to do with the subject at hand.

Which lights are you referencing?

Worthless - I agree, why? - The lights “most” buy, nearly all aren’t even UVB range which is 280-315nm, most are more like cheap weak end UVA @390nm or so…

UVB absolutely delivers the goods; experiment more and rely on others studies & agendas less would be my humble advice

UVB alone is what one wants, UVA gets in the way, dig into Vitamin D synthesis in animals and you’ll find something very much in common, plants crave UVB just like reptiles, AND Humans, most all complex life needs its UVB in fact…

I posted way too much about this here gosh 7-8 years or so ago now, wow does time fly

Peace

 

[Rocket Soul]

Which lights are you referencing?

Worthless - I agree, why? - The lights “most” buy, nearly all aren’t even UVB range which is 280-315nm, most are more like cheap weak end UVA @390nm or so…

UVB absolutely delivers the goods; experiment more and rely on others studies & agendas less would be my humble advice

UVB alone is what one wants, UVA gets in the way, dig into Vitamin D synthesis in animals and you’ll find something very much in common, plants crave UVB just like reptiles, AND Humans, most all complex life needs its UVB in fact…

I posted way too much about this here gosh 7-8 years or so ago now, wow does time fly

Peace

I wouldnt count on a reply from him. OP joined the same day as he posted this question. And has only ever posted in this thread, just a few times, then bolted. Its typical sock puppet account behaviour; its someone who wants to stir shit up without using his main account, my bet at least.

 

[led05]

I wouldnt count on a reply from him. OP joined the same day as he posted this question. And has only ever posted in this thread, just a few times, then bolted. Its typical sock puppet account behaviour; its someone who wants to stir shit up without using his main account, my bet at least.

Agree completely about OP however This Discussion/thread is still valuable, very valuable in fact imo so I’m appreciative it was started …

I appreciate the other posters & your content too and what’s been offered up,

- I do find it interesting how many commonalities exist with more “professional/ lab experiments cited here subsequent” to the work I posted a long time ago BF anyone was talking / marketing UVB, but more knowledge shared & spread the better

Peace brother !

 

[argylia]

You're welcome. There are other recent papers that came to same conclusion (lack of statistical significance) below. There is one application method for UV-B that may (although unlikely) yield beneficial results using intermittent UV flux. For example, every other day for a short period to reduce DNA damage and prevent the plant from synthesizing protective compounds to reduce UV absorbance. There is some research on going in that regard, but it's not especially promising.

Frontiers | Cannabis Inflorescence Yield and Cannabinoid Concentration Are Not Increased With Exposure to Short-Wavelength Ultraviolet-B Radiation

Before ultraviolet (UV) radiation can be used as a horticultural management tool in commercial Cannabis sativa (cannabis) production, the effects of UV on ca...

www.frontiersin.org

Frontiers | Indoor grown cannabis yield increased proportionally with light intensity, but ultraviolet radiation did not affect yield or cannabinoid content

Cannabis (Cannabis sativa) flourishes under high light intensities (LI); making it an expensive commodity to grow in controlled environments, despite its hig...

www.frontiersin.org

Interesting! I was looking for papers like those. Maybe it doesn't work for productivity. But I think it can be a nice tool for adapting individuals to new enviroments. Maybe, considering light intensity variation during the day (like clouds in "the field")

 

[yesum]

I more or less gave up on uvb for my plants. It was a hassle and not much or any difference that I could detect.

I am more interested in how different wave lengths can change chemical ratios or make certain compounds change for the better in terms of how the high expresses itself. I think thc percentages are not going to change much from uv and not what I care about very much. If I run a certain strain with uv and the high is better, then for sure I continue. I never had that happen yet.

Outdoors here in cali the light dep crops harvested during peak sun light/middle of summer, are more potent than when harvested later in the fall or winter months. The spectrum of light in summer in California is blue and not 3000K or anything like what many use to grow indoors, I use 6500K all the way thru. Most likely it is the intensity of overall light and not added uv that is making the plants more potent in the light dep plants.

 

[purple_man]

high fambz,

ive been away for a while, and you guys remind me why!!!

any of you guys are capable of doing 1:1 tests on the same phenotype, and in the end cs/ms ing the product???

thought so!

so much bs still left in the game!!!!

may god forgive you snakeoilers

blessss

 

[yesum]

^^ No I did not do a scientific type deal with clones and sending them to a lab. Doubt I will as I have so many strains to deal with and issues with them. Lazy is another cause.

So what is the real deal here, it would appear you know.

 

[Ca++]

I think the word snakeoil was the on topic bit. The rest was mostly the posters state of mind. He did edge upon our lack of decent test gear, beyond scales and consuming it. Though as most is grown for consumption, testing it through consumption is valid. The lab might seem better, but the lab is still today identifying things they can now look for. Even when they can see what's present, the effect on the consumer isn't known, until the consumption test is done. The lab is just a tool, to assist consumption based testing. Alone, it's not superior. As a case study of labs, we can see they looked at cannabis, found thc seemed the special and abundant bit, and made it the de-facto measurement of pot quality. The learning curve is still on it's way up, and it this was a coaster, the top is still in the clouds. However, we are consumers, and the best way to see how much a consumer likes it, is through consumption. The lab can say 20% thc is better than 18% thc, but there is just too much they are not able to tell us.

I'm quite wide eyed, looking at some developments in test gear. Specifically, the shrinking of tech. That used mass spec for $10,000 comes on a truck, and I can't even work it. The parts bill will be pretty special to, and they might not exist for your 10yo machine. It's not been viable.
Now they have this stuff down to hand device size. Through targeting the measurement capabilities needed, and not providing for your burger relish testing, a few specific sensors have appeared. Our smart phone cameras show us just how pixel dense sensors have become. Which is making light diffraction measureable over shorter distances. Meanwhile LED tech is making light bands accessible, without a range of healing crystals that could really do with shoving somewhere. We are close to owning handheld devices, that can do most tissue sample jobs, in our own gardens.

Fuck me am I excited. It's like Christmas is tomorrow, and I'm getting a Lotus

 

[purple_man]

attaboy ca++ got it!

the original post was made about genetical integrity of the so called name brands nowdays...

back in the day when we started, it was no names, no tags, little knowledge, let alone marketing name game....

it*s all about the appreciation of the complete cannabinoid and terpene profile, which pleases a certain variant of the endocannabinoid and biochemistry profile of the user.

ie.: everyone likes/reacts differennt to the same freaking sample/bud/hasj, hence call it what you wanna call it, most important is you like it, it helps you with whatever ailes you.

BUT, never go around promoting some bogus fake names, or whatever bs, let the user decide, hence dont follow the hype or what anyone tells you, unless you tried and liked it (and if so, keeep that clone alive, it*s a 1 in a billion find, even if you seek her from the same seedbatch, THE EXACT same one will never resurface ).

blessss
ps.: let alone doing different PAR frequencies, hance, G + E = P (Genetix + Environment = Phenotype), you modulate one of those even to a minimum the phenotypical expression will differ... E equals temps, food, light intensity n spectrum, etc....)

pss.: have some fun while tweaking those Es n Gs, it will make for some better Ps

psss.: all my incandescence bulb bros initial trialists holla

 

[Rocket Soul]

So test grow is over, dried and cured. The best results; subjective smell, taste and potency, came from a tray with high red (2700k 90cri + 660nm) and some uva, divided 2:1 between 400nm and 365nm. Hard to say how much it was since it was china diodes and the drive current wasnt known but my best guess is about somewhere around 8% of total light but really just guessing.
Uvb tray was hard to evaluate as it was out of the door before early and it wasnt the same base white spectrum.
Going forward im looking more towards uva than uvb, but still want to try high red + uva +uvb before id let go off uvb.
One thing im sure off is getting uvb at 285nm rather than 295 though.

 

[CharlesU Farley]

So test grow is over, dried and cured. The best results; subjective smell, taste and

Just curious, do you ever do double blind, a/b tests?

I stopped playing around with light manipulation after my Lumigrow 325 but have always been intrigued with additional UV lighting. Just never thought it would really add enough "bottom line" THC to be worth the effort, at least for me. I already grow more than I can consume.

I respect your knowledge of lighting.

 

[Ca++]

So test grow is over, dried and cured. The best results; subjective smell, taste and potency, came from a tray with high red (2700k 90cri + 660nm) and some uva, divided 2:1 between 400nm and 365nm. Hard to say how much it was since it was china diodes and the drive current wasnt known but my best guess is about somewhere around 8% of total light but really just guessing.
Uvb tray was hard to evaluate as it was out of the door before early and it wasnt the same base white spectrum.
Going forward im looking more towards uva than uvb, but still want to try high red + uva +uvb before id let go off uvb.
One thing im sure off is getting uvb at 285nm rather than 295 though.

Men in white coats are boasting about 7.5% efficiency for UV LEDs. That is in their lab. It's conceivable that 8% of your light output in the UV region, would mean a UV rig consuming as much power as your main lights. I did a brief search for what we can buy, and found a 1.9w LED producing 0.055w of UV. That's not a tenth of what a compact fluorescent produces. These sort of numbers just don't work. It's why the EU has effectively banned flo's, except for UV generation, where there is no alternative.