Should I add UVB Light?

[DennisBrown]

Have you noticed a difference in response or tolerance from cannabis from different regions? Certainly different parts of the globe have different uv regimens....

Absolutely, and in some cases, a radical difference. In general, Indicas can handle 2 or 3 times more UV than sativa. That makes sense since indica is a high mountain strain, and the higher you go, the less atmosphere there is to filter the UV, so really high mountain strains had to evolve a much higher tolerance. One of my testers, Walter P. Haze, had me build him a custom fixture to use on some OG Kush. Real stuff, shipped from the middle east. Instead of 1 bulb at 20 watts, it had two bulbs, 80 watts each, so 160w total. 8X the normal UV. I have a few crazy testers like that, who want to push the envelope, way beyond good judgement. He had to work them up over several weeks, but they could take several hours a day. That would fry a sativa.

 

[Brendanpre]

Lol. I think you would have no problem finding some crazy testers like that right here.

 

[MIMedGrower]

Probably worth mentioning that NO UVB LEDs exist that work. UVA, sure, and UVA is great for photosynthesis, but UVB LEDs in any spectrum that is worthwhile, do not exist. Every week I'm talking to makers, but UVB is a special pocket of frequencies that tends to burn out or destroy the packaging. Any LED that says "UV" is really talking about UVA only. Until they get UVB below 300nm that won't burn out after 100 hours, fluorescent is the only game in town for UVB. MH, CMH, etc, all have a tiny amount of UVA, no UVB.

This chart from the university of Utah shows Phillips cmh 315 elite Agro has some. Other tests have shown the 4-5% thc increase just using the cmh bulb. I didn’t find it but there is a chart of the 4000 k bulb showing more than the 3100k.

http://ceac.arizona.edu/sites/default/files/utah_state_-_spectral_analysis.pdf

I have not seen claims of an 8% increase until your post here.

my biggest question is why is a thc increase with no other cannabinoids increasing such a good thing? The only benefit I see is higher prices for the dispensary for the bigger number.

we blind tested patients and no one could reliably pick the higher thc weed. The lab showed a 3% increase with the cmh bulbs on the blue lemon Thai strain. I got it wrong half the time too. Hortilux super hps 600w vs Phillips 315 cmh 3100k. We are still growing with hps after a lot of side by side testing. I do like combining hps and cmh best for plant health and structure. But that is really the same as 2-1 hps to mh.

and many growers have cost themselves yield experimenting with UV fluorescent bulbs. Tons of diaries out there showing damage. Seems a fine line between effective and harmful.

and of course it’s harmful to us too.

 

[DennisBrown]

Wow! Thanks for this needed Info! So awesome! My last grow had them on the whole time, In A greenhouse. For sure, much more sand in the bags. Smoke was more potent than previous. And also have a more ceilingless high. did three hours middle of day. I did however, have a complete change of expression from a cbd plant. I expected a typical cbd warm shower type buzz from Harley m.d. but the buzz from this pheno is not relaxing at all. Have you found any evidence of uvb changing cannabinoid expression? Maybe its just an outlier. Thnx

Well, it kind of does by design. From out limited testing, we haven't seen much any change in the other 130+ cannabinoids, but that makes sense, since only THC is used as "sunblock" and all we are doing is forcing it to make more "sunblock". What you end up with is more total cannabinioids, but the minor ones haven't changed, only THC has. So if you have 1% CBD and 20% THC and now you have 1% CBD and 28% THC (plus more terpenes), you have changed the profile radically even though only THC has changed. Before, CBD was 5% compared to THC (1/20th as much CBD as THC), now it is 3.5% (1/28th as much CBD as THC). Since CBD acts as a moderator for THC (as do other cannabinoids), the REALITIVE amount of them is lower compared to the higher THC, even if the absolute amount is the same. For people prone to anxiety, this might not be a good thing.

Within a year, I want to do some testing on high CBD plants, like 1:1 or 1:3 CBD vs THC. These tend to be around 10-12% THC is all, but I'm hoping to see what we can do to bump them to at least 15%, with at least 5% CBD. This would be very useful for people with anxiety and a more relaxed buzz for anyone, while still being reasonably potent. A lot more potent than the brick weed we used to smoke in Texas back in the late 70s for sure.

 

[Brendanpre]

From what you are saying, I'm starting to think of it more in terms of the way we tan in the sun. The more UV we are exposed to the darker our skin gets, not 100% sure about this but I think it is melatonin that does this in our bodies.

If someone who gets no sun exposure and is very pale spends time in the sun they are more likely to get sunburned rather than tan. Just like plants burn if we give them too much UVB all at once. But if we start slowly and allow time to adjust( tanning a little every day), just like our skin gradually gets darker with more melatonin, plants will develop more THC. And, following on from this, just like we can handle more sun exposure without burning as we tan darker and darker, the plants will handle more UVB as they adjust and produce more THC.

@Moe.Red @Milson good move giving the ladies a "cloudy" day to get over their sunburn.

 

[DennisBrown]

This chart from the university of Utah shows Phillips cmh 315 elite Agro has some. Other tests have shown the 4-5% thc increase just using the cmh bulb. I didn’t find it but there is a chart of the 4000 k bulb showing more than the 3100k.

http://ceac.arizona.edu/sites/default/files/utah_state_-_spectral_analysis.pdf

I have not seen claims of an 8% increase until your post here.

my biggest question is why is a thc increase with no other cannabinoids increasing such a good thing? The only benefit I see is higher prices for the dispensary for the bigger number.

we blind tested patients and no one could reliably pick the higher thc weed. The lab showed a 3% increase with the cmh bulbs on the blue lemon Thai strain. I got it wrong half the time too. Hortilux super hps 600w vs Phillips 315 cmh 3100k. We are still growing with hps after a lot of side by side testing. I do like combining hps and cmh best for plant health and structure. But that is really the same as 2-1 hps to mh.

and many growers have cost themselves yield experimenting with UV fluorescent bulbs. Tons of diaries out there showing damage. Seems a fine line between effective and harmful.

and of course it’s harmful to us too.

It's all about the right spectrum of UVB, not the highest absolute UVB. As far as yields, every test we've sponsored showed virtually no change in yield. These were highly controlled tests with clones, not anecdotes, which is how rumors get around.

As for "should I use UVB?", the answer to that is different for different people. Let me be clear, we aren't trying to get the absolute highest THC level for maximum dollar at the dispensary. Most of our growers that I talk to are growing less sexy strains that are simply excellent medical strains, and they want to boost the THC some. White Widow and Northern Lights are two of the most common. These aren't super high THC strains, but they have a great overall cannabinoid profile. Some growers use our Flower Power purely to bump the THC a few points, some just for mildew (we are talking medical here) and others want both. I tell people right up front, if you are running some crazy 40% strain, we aren't the solution to get it magically to 50%. If you want to get the most of a great medical strain, we can do that. 15 to 30% increases (not total, but increase) is very common.

As for safety, that is pretty easy. All our kits have glasses, you generally only run them 2 to 3 hours a day, so its easy to run when you aren't around. I work around UV all the time, have for 30 years without issue, it isn't hard to protect yourself. The main thing is your eyes. I actually expose my hands on purpose regularly, as it helps with some mild psoriasis. We all need some UVB, just not too much. UVB is how we get vitamin D. No food other than mushrooms has it naturally, so we evolved to not only tolerate it, but our body requires it. Just don't over do it.

Short version: It isn't for everyone, but it works well if you have proper goals.

 

[Milson]

Absolutely, and in some cases, a radical difference. In general, Indicas can handle 2 or 3 times more UV than sativa. That makes sense since indica is a high mountain strain, and the higher you go, the less atmosphere there is to filter the UV, so really high mountain strains had to evolve a much higher tolerance. One of my testers, Walter P. Haze, had me build him a custom fixture to use on some OG Kush. Real stuff, shipped from the middle east. Instead of 1 bulb at 20 watts, it had two bulbs, 80 watts each, so 160w total. 8X the normal UV. I have a few crazy testers like that, who want to push the envelope, way beyond good judgement. He had to work them up over several weeks, but they could take several hours a day. That would fry a sativa.

That makes sense...as i have been thinking more about it, i would expect the afghani plants to be less protected than sativas in a jungle....

Sorry to keep peppering you. I have gotten into thin layer chromatography lately on my homegrown (under "full spectrum" led) and found surprising levels of cbg across several strains. I have read studies showing a relationship between blue light and cbg. I'm wondering if you have found any synergies there. Since they share a precursor, i am curious.

Fwiw i use a 26w reptile lamp inches from the plant i am treating in my little (3 ft by 3 ft tent) because any of your products would fry my plants (just don't have the clearance).

 

[DennisBrown]

From what you are saying, I'm starting to think of it more in terms of the way we tan in the sun. The more UV we are exposed to the darker our skin gets, not 100% sure about this but I think it is melatonin that does this in our bodies.

If someone who gets no sun exposure and is very pale spends time in the sun they are more likely to get sunburned rather than tan. Just like plants burn if we give them too much UVB all at once. But if we start slowly and allow time to adjust( tanning a little every day), just like our skin gradually gets darker with more melatonin, plants will develop more THC. And, following on from this, just like we can handle more sun exposure without burning as we tan darker and darker, the plants will handle more UVB as they adjust and produce more THC.

@Moe.Red @Milson good move giving the ladies a "cloudy" day to get over their sunburn.

UVB makes your skin produce melanin. UVA (specifically around 365nm) causes that melanin to combine with oxygen (oxidize / tan). I've actually written over 100 articles on tanning humans back in the 1990s. :) But THC is like our tan. Once our skin tans, it starts to block UV, so we make our own sunblock.

You don't have to work plants up so gently. You can start with a pretty good burst. Plants can tolerate a lot more UV than humans because evolution has made them do so. You and I can walk into the shade. Plants can't, so they had to evolve mechanisms to tolerate levels of UV that would be very harmful to animals.

 

[DennisBrown]

That makes sense...as i have been thinking more about it, i would expect the afghani plants to be less protected than sativas in a jungle....

Sorry to keep peppering you. I have gotten into thin layer chromatography lately on my homegrown (under "full spectrum" led) and found surprising levels of cbg. I have read studies showing a relationship between blue light and cbg. I'm wondering if you have found any synergies there. Since they share a precursor, i am curious.

Fwiw i use a 26w reptile lamp inches from the plant i am treating in my little (3 ft by 3 ft tent) because any of your products would fry my plants (just don't have the clearance).

We have lamps for close up growing, like the Universal UV, which was one of our first canna lamps. F32T8, 7% UVB 93% UVA, no VIS, with the spectrum pushed down below 300nm, so the "burn factor" is closer to a 10%. Can be run from 15 to 60w, although F32 standard (20 real watts) is typical.

As for CBG, I honestly don't know. We work really hard to make our lamps so they produce as little visible light as possible, so they don't interfere with what else you are doing. I have no reason to think that UV itself would affect CBG, but we've never tested for it.

 

[Brendanpre]

Oops! Lol. I always get confused between melanin and melatonin. Those high school biology lessons are a bit fuzzy after 20 yrs ...

 

[sshz]

There are numerous contradictions from some comments made above and those in Dr. Bruce Bugbee's (Utah St.) video's on uv-b......... I'm not saying which are correct or not, but I found 4 already in a quick read. Take everything with a grain of salt, and do not rely on this one or that one as being correct.

I will say Dr. B has no skin in the game, and has been researching lighting and marijuana specifically for many years, and tends to be the "standard" when it comes to these things. I'm trying to keep an open mind, but it's important to understand everyone's motivation and ulterior motives when posting specific products and claims.

I will say I think each person's personal experience while using UV-B would probably be the best source of relevant info on the subject. Moe is off to a good start, and I'll be introducing UV-B to my room in just a few weeks. So let's not jump to an conclusions just yet, the ship has just left the harbor.

 

[Milson]

We have lamps for close up growing, like the Universal UV, which was one of our first canna lamps. F32T8, 7% UVB 93% UVA, no VIS, with the spectrum pushed down below 300nm, so the "burn factor" is closer to a 10%. Can be run from 15 to 60w, although F32 standard (20 real watts) is typical.

Found it. Interesting. So i can just tuck one of these into a hardware store fixture and be good in a little tent? If so happy to try it.

Again, i know I'm badgering you and I appreciate your time. You mention uv-c on your site. The manual that came with my tlc kit made this claim about uv-c and thcv. I know uv-c is quite dangerous and tbh i was surprised to see this. They gave no references. Just wondering if that rings a bell for you.

 

[DennisBrown]

There are numerous contradictions from some comments made above and those in Dr. Bruce Bugbee's (Utah St.) video's on uv-b......... I'm not saying which are correct or not, but I found 4 already in a quick read. Take everything with a grain of salt, and do not rely on this one or that one as being correct.

I will say Dr. B has no skin in the game, and has been researching lighting and marijuana specifically for many years, and tends to be the "standard" when it comes to these things. I'm trying to keep an open mind, but it's important to understand everyone's motivation and ulterior motives when posting specific products and claims.

I will say I think each person's personal experience while using UV-B would probably be the best source of relevant info on the subject. Moe is off to a good start, and I'll be introducing UV-B to my room in just a few weeks. So let's not jump to an conclusions just yet, the ship has just left the harbor.

I small section of a video where they were comparing lamps using the UVB rating. I showed it to a couple of friends in the UV industry, and they found it amusing. You can't compare lamps by UVB ratio, it doesn't work that way. I have two 34% UVB bulbs, once is 30% stronger than the other, same wattage. I have a 7% lamp that uses a custom phosphor that will easily beat a regular 10% lamp. I actually have designs on file where a 10% lamp would have more burn potential than a 20%.

Percentages are useful when you are comparing identical lamps that use identical everything except phosphor blend. I put an image on the Facebook page explaining it, but in short, a 10% UVB that is centered at 313nm (common) will burn you in a few minutes. A UVB device that peaks at 280 will fry you in short order, even though both are "10%". The energy level goes up exponentially as you go from 320 to 280nm. The percentage is a relative value, not an absolute, and while it has some uses, comparing dissimilar lamps is not one of them.

 

[DennisBrown]

Found it. Interesting. So i can just tuck one of these into a hardware store fixture and be good in a little tent? If so happy to try it.

Again, i know I'm badgering you and I appreciate your time. You mention uv-c on your site. The manual that came with my tlc kit made this claim about uv-c and thcv. I know uv-c is quite dangerous and tbh i was surprised to see this. They gave no references. Just wondering if that rings a bell for you.

View attachment 1109341

Honestly, we strongly suggest avoid UVC for plants, assuming we are talking about 256nm clear UVC bulbs. It's not quite as dangerous as some people make out, although it is dangerous. It can't penetrate the eye and hit the retina like UVA can, for instance, and it only penetrates a few layers of skin, so yes, you can get a NASTY flash burn but it isn't deep. The utility for cannabis just isn't there. The *entire reason* we use UVB for cannabis is to trigger the UVR8 protein, and UVC doesn't do that very well. The main band that triggers it is 285-288nm (around the same place your skin makes vitamin D).

In fact, I never carried any UVC lamps until flu hit, which we started carrying as a defense for staying open, as that technically made us essential. Most of our sales of UVC are wholesale to Canadan OEMs for germicidal use. I have refused to sell it to a grower before. We know UVB works, the risks are much more manageable, the bulbs are much less fragile (UVC requires quartz glass, which is very brittle).

I have a research paper laying around here somewhere, Texas A&M working with the US Dept of Agriculture, using our lamps, and specifically, it is the UVR8 protein that is being studied. Dr. Robert Klein. I need to dig it up, although it is pretty dry reading. Here's an article that is more straight forward. I don't get why so many "experts" do not understand or know about UVR8 when it is so well documented.

UVR8 - Wikipedia

en.wikipedia.org

 

[DennisBrown]

There are numerous contradictions from some comments made above and those in Dr. Bruce Bugbee's (Utah St.) video's on uv-b......... I'm not saying which are correct or not, but I found 4 already in a quick read. Take everything with a grain of salt, and do not rely on this one or that one as being correct.

I will say Dr. B has no skin in the game, and has been researching lighting and marijuana specifically for many years, and tends to be the "standard" when it comes to these things. I'm trying to keep an open mind, but it's important to understand everyone's motivation and ulterior motives when posting specific products and claims.

I will say I think each person's personal experience while using UV-B would probably be the best source of relevant info on the subject. Moe is off to a good start, and I'll be introducing UV-B to my room in just a few weeks. So let's not jump to an conclusions just yet, the ship has just left the harbor.

Skepticism is good, but the ship left years ago. We've been supplying lamps for 20 years, it was written about back in the 1980s, and Ed Rosenthal swears he has found literature from 100 years ago on it. Again, skepticism is always good. It's one reason we give a 90 day money back guarantee. When I first started with this, it was hard to even find testers since it was illegal just about everywhere and sounded "too good to be true", so I'm no stranger to skepticism.

 

[Edinburgh]

If your growing for your dads pain run some royal purple kush or sodk those strains help with my pain and i have reflex sympathetic dystrophy syndrome commonly called the suicide syndrome these strains help me a bit.

 

[shaganja]

Well, it kind of does by design. From out limited testing, we haven't seen much any change in the other 130+ cannabinoids, but that makes sense, since only THC is used as "sunblock" and all we are doing is forcing it to make more "sunblock". What you end up with is more total cannabinioids, but the minor ones haven't changed, only THC has. So if you have 1% CBD and 20% THC and now you have 1% CBD and 28% THC (plus more terpenes), you have changed the profile radically even though only THC has changed. Before, CBD was 5% compared to THC (1/20th as much CBD as THC), now it is 3.5% (1/28th as much CBD as THC). Since CBD acts as a moderator for THC (as do other cannabinoids), the REALITIVE amount of them is lower compared to the higher THC, even if the absolute amount is the same. For people prone to anxiety, this might not be a good thing.

Within a year, I want to do some testing on high CBD plants, like 1:1 or 1:3 CBD vs THC. These tend to be around 10-12% THC is all, but I'm hoping to see what we can do to bump them to at least 15%, with at least 5% CBD. This would be very useful for people with anxiety and a more relaxed buzz for anyone, while still being reasonably potent. A lot more potent than the brick weed we used to smoke in Texas back in the late 70s for sure.

Wow. Thanks so much! The knowledge you have is so rare! Thanks for sharing!

 

[Moe.Red]

You don't have to work plants up so gently. You can start with a pretty good burst. Plants can tolerate a lot more UV than humans because evolution has made them do so. You and I can walk into the shade. Plants can't, so they had to evolve mechanisms to tolerate levels of UV that would be very harmful to animals.

Having done this before and essentially burning the leaves up in the process, I'm trying to understand why my results are different.

How many uW/cm2 should I be expecting for "a pretty good burst?"

Am I being over cautious in listening to the plants?

 

[Moe.Red]

I'm not sure what to look for in terms of recovery from our cloudy day. I need to determine what light period to run today. I'm not seeing any change to make me think the taco leaves are coming back with time. I'm a few hours away from taking the daily samples, so we can still run today if it makes sense.

Also PH has stabilized.

 

[Milson]

I'm not sure what to look for in terms of recovery from our cloudy day. I need to determine what light period to run today. I'm not seeing any change to make me think the taco leaves are coming back with time. I'm a few hours away from taking the daily samples, so we can still run today if it makes sense.

Also PH has stabilized.

Go back to the same imo. Let's see how she is doing with her sunscreen production. We should see the rate of deterioration at least slow down imo.

Unless it straight stops (deterioration), idk why you would increase. According to my understanding, we are essentially dealing with an underdeveloped mechanism vs what we would expect in nature. The plant is catching up because it has the tool in its kit it just wasn't expecting this now when it wasn't experiencing it previously.

Maybe.