UV light, adding to LED grow?

[Emilya Green]

Didn't miss it, and was not offended... I just hate being shut down and my ideas discounted because someone thinks they have found a loophole... and can claim that I can't document my facts to their satisfaction. It should be sufficient among friends that I had an opinion on this matter and it should be taken at face value that I did the experiment that I spoke of and came up with the conclusions that I did, but you told me that this was not useful. No... no offense taken; just noting a common debate technique in use here that I abhor. Feel free to pontificate as you wish, for the wind has been taken out of my sails and you are now all alone in a drifting sea of theoretical chatter. Good luck in your future experiments.

 

[TorturedSoul]

I don't know what to say (type) here, lol. I would try, "Maybe you should try cultivating less tender sensibilities, that way you could participate in more things (on the forum... in life in general) without fear of falsely feeling that others are denigrating you," but experience has shown me that more than 50% of the time when things have progressed to the point when such a statement becomes warranted, the person being addressed is actively looking for things to be... bothered about. So... Yeah, there probably isn't anything that I could communicate that would help. Which saddens me a little; but I'll get over it, of course. Still and all, it is a shame to think that a voice can fade away so easily from a useful discussion, and the knowledge which might have been shared, won't be. I shall go ponder this. Perhaps I'll think of something that I can add to my .SIG, maybe a notice that the universe isn't out to get any one individual (and neither am I ).

I found specific UV tube lights from a company called solacure

That company looks pretty interesting, as do its products; thanks for mentioning it by name. I had previously only been considering ReptiSun and Arcadia reptile lighting. And - momentarily - digging the old mercury vapor plant killer out of the shed, but that thing is a menace (and buzzy). At first glance, I thought solacure's products were a bit pricey. But, upon reconsideration, realizing that they undoubtedly move a relatively low number of products each year, and deal with applications that tend to involve a fair amount of money... not too bad, after all. Especially if they perform as advertised. I wonder if they'd consider becoming a forum sponsor? It would help them become better known in the cannabis "industry," and give them opportunities for product testing/feedback - a potential win/win.

 

[DET—PDX]

I don't know what to say (type) here, lol. I would try, "Maybe you should try cultivating less tender sensibilities, that way you could participate in more things (on the forum... in life in general) without fear of falsely feeling that others are denigrating you," but experience has shown me that more than 50% of the time when things have progressed to the point when such a statement becomes warranted, the person being addressed is actively looking for things to be... bothered about. So... Yeah, there probably isn't anything that I could communicate that would help. Which saddens me a little; but I'll get over it, of course. Still and all, it is a shame to think that a voice can fade away so easily from a useful discussion, and the knowledge which might have been shared, won't be. I shall go ponder this. Perhaps I'll think of something that I can add to my .SIG, maybe a notice that the universe isn't out to get any one individual (and neither am I ).



That company looks pretty interesting, as do its products; thanks for mentioning it by name. I had previously only been considering ReptiSun and Arcadia reptile lighting. And - momentarily - digging the old mercury vapor plant killer out of the shed, but that thing is a menace (and buzzy). At first glance, I thought solacure's products were a bit pricey. But, upon reconsideration, realizing that they undoubtedly move a relatively low number of products each year, and deal with applications that tend to involve a fair amount of money... not too bad, after all. Especially if they perform as advertised. I wonder if they'd consider becoming a forum sponsor? It would help them become better known in the cannabis "industry," and give them opportunities for product testing/feedback - a potential win/win.

They say there are multiple universities that use their UV lights so idk, It might be worth the 150.00 USD to experiment but then again.. maybe not. Could just be a marketing ploy but they can’t false advertise without being sued, I guess I could call the horticulture departments at missisippi state and a few others and try to confirm but why bother. I do know from my own research the mentioned universities have horticulutre and cannabis research departments though. There’s no reason to use UV lights except for subtropical and tropical plants to my knowledge. I think maybe I’ll try red lighting first because that is sure to add benefits in flower. Then when I get a few more checks put away invest in the UV light.

 

[PurpleGunRack]

The idea is to mimic the solar radiation you get in the famous hash producing mountain areas like Hindu Kush, Rif Valley etc.

This is about it when it comes to the scientific part of it [PDF] UV‐B RADIATION EFFECTS ON PHOTOSYNTHESIS, GROWTH and CANNABINOID PRODUCTION OF TWO Cannabis sativa CHEMOTYPES | Semantic Scholar


LEDs don't come in UV-B wavelengths, but they do come in UV-A.


Before even considering adding stuff like UV, Far Red etc. you should fully saturate your flowering space with the main light, as in 1000w SE HPS per m2 or 600w high end COBs/MPDs per m2.
Giving your plants the amount of photons (DLI) they need is much more effective than playing around with spectrum-tweaking

I think adding the red (660 nm) is a much better idea, and it's easier in practical application

 

[Aroxol]

Good luck with the solacure, please lmk how they do for you (if you notice a difference). Here’s the DIY build I just put together, 12 intermixed IR/UVA COBs attached to heatsink. The small white boards are the far right spectrum initiators. Happy growing all.

 

[TorturedSoul]

Here’s the DIY build I just put together, 12 intermixed IR/UVA COBs attached to heatsink. The small white boards are the far right spectrum initiators.

How's that working for you? Notice any benefit (or harm) from using it?

I remembered this thread just now, as I was reading this article:

LED efficacy, UV, and plant feedback highlight horticulture presentations (MAGAZINE)

The second US Horticultural Lighting Conference was packed with informative presentations, reports Maury Wright, with prevailing themes including SSL comparisons with legacy lighting...

www.ledsmagazine.com

...and thought I'd post the link to it here in case anyone else would find it to be of interest. Among other things, I had no idea that there's a company (Seoul Viosys) focused entirely on UV LEDs.

 

[Grassmaster]

I don't notice any difference in potency when using my 315 CMH or my COB system. I would just get a light that's known to give off the UV instead of adding it, as you don't know how much to use.

 

[Aroxol]

Hey TS, how are you man, hope all is well. Thanks for the article, Colorado State has very strong horticulture and agricultural teams so it’s a great source. My IR/UVA setup had no negatives impacts that I experienced, so on that front everything was good. In terms of did it impact potency, I really have no idea. I know my version smell and tastes great, which deviates from some strain reviews I’ve read online, so there could be some anecdotal evidence to support UV improving smell/ terps I suppose.

I change up my grows almost every single time, which is fun but makes it difficult for me to say with any certainty which parts made the biggest difference.

I really enjoyed how my bulk turned out, that’s all I know!

 

[Etzmishpat]

I’m adding the UVB booster from california light works but only for the last 3-4 weeks.

Going to hit them with the UVB at 36 inches for:

Dose tritrarion 1: half an hour per day week 3 of flower.

Dose tritration 2: 3x 1 half hour every 60 mins at 36 inches for weeks 4-finish

I’ll let everyone know with pics what happens.

I have a control plant in a different tent - only 3 plants will get the UV. All other factors will be the same including lighting until week 3 flower.

Resin comparison should be interesting.

 

[Etzmishpat]

Also, i have a UVA/B meter, Id be happy to measure and post the lights I have access to:

HLG 100 V2 4000K QB
CF Grow CXB COB 3590
[non sponsor brand name omitted] P300LED

 

[Aroxol]

Wanted to follow up on this thread as I’m noticing some negative effects I believe are from my UVA/IR. Turned on my light a few days ago in my cabinet and am now seeing signs like below. Worth noting that during my last grow of Incredible Bulk grow I also noticed some adverse signs of damage within a week of turning on the UVA/IR lights, but ultimately chalked it up to thinking it was a nutrient issue/ my lack of experience with DWC...however after seeing my current plants respond to the light being turned on for just a few days at low strength, I’m starting to reconsider that thought.

I didn’t notice anything spectacular in terms of trich coverage from my last grow, so where I’m at is I just turned off and removed the light altogether right now. Not sure what others are seeing as this is a somewhat new field of study, but in my cases I’m feeling like my light may actually doing more harm than good. I built mine from rapidled, so this could just be related to my specific build but seemed worth sharing.

@oldsalt @Emilya @TorturedSoul

My build: dimmable 12 cob intermixed bar.
-Ultra Violet UVA LED (390-400nm)
-Infrared LED (840-870nm)

 

[Grassmaster]

I get similar spots on leaves if the plants aren't old enough and the light is too close or Par too high. Sometimes I have to turn it below 300 PAR when the plants are young. Their is 0 advantage of turning the light up higher than what the plant needs to fulfill it's genetic potential.

 

[Aroxol]

Agreed, my light achieves its purpose, just a little too well. It’s designed to hurt the plants, which it does, but even at low strength it’s beyond what I’m looking for.

 

[Mars Hydro]

uvb will help a little, but please not too much, you can add a T5 to add the uvb.

 

[Etzmishpat]

I think the UVB may have made the plant under it too resinous to grow normally. I’ll have pics soon.

I put the UVB on 11 hours for about a month... the plant under it is the stinkiest skunky thing I’ve ever encountered.

the little buds are so covered in resin that it’s like they’re covered in plastic.

 

[shams]

Agromax t5 bulbs are top of the line and produce much better and more efficiently than any other bulb

 

[Buds Buddy]

I have been looking into this a little because the brand of LED lights that I am buying right now include both the IR and UV spectrums in these full spectrum lights. I am skeptical about the need of the UV light full time, because some years ago we did some experiments with turning on UV light (lizard lamp} for 1-2 hours at midday to simulate the sun's energy at high noon. We didn't move our lights, and assumed that the full UV rays that the sun hits us with quickly go away when the angle of the sun changes, and simulated that by only having the 1-2 hour windows. We did seem to notice an increase in trichome production on the plants getting this treatment.
IR or deep red light is another thing, and again my new LED array allows me to experiment with this on full time too. Back in the day I would have a halogen flood lamp set to come on for 15 minutes at sunrise and sunset in the tent. This simulated the setting and rising sun low on the horizon and those deep red hues that are displayed during those times of day. The theory is that the plants use this deep red light to judge where they are in relation to the horizon, and knowing this keeps them from stretching so badly. Greenhouse operators call these "trigger lights" and they have been used for decades, usually at both ends of a greenhouse.

So if the Far Red Lights trigger / replicate the sun coming up or going down would the placement of the lights make a difference. For instance in a 7' tent: Would you have Far Red at the Top of the tent to simulate Sun up & Far Red say at 4' (I try to keep my plants under 4') to simulate Sun down... or wouldn't that make any difference ?
I'm working on adding Far Red to my tent so any info is very helpful. Thanks !

 

[Emilya Green]

So if the Far Red Lights trigger / replicate the sun coming up or going down would the placement of the lights make a difference. For instance in a 7' tent: Would you have Far Red at the Top of the tent to simulate Sun up & Far Red say at 4' (I try to keep my plants under 4') to simulate Sun down... or wouldn't that make any difference ?
I'm working on adding Far Red to my tent so any info is very helpful. Thanks !

I have read that the plants use the far red to gauge their height in relation to the horizon and this is how it affects internodal spacing. I never worried about that part of it, mostly intending to wake the plants up fast and put them to bed fast, so I just hung my far red emitter above the canopy so that all the plants could see it. It did seem to work though, in both respects... so I really don't know what difference it would make.

 

[Buds Buddy]

I have read that the plants use the far red to gauge their height in relation to the horizon and this is how it affects internodal spacing. I never worried about that part of it, mostly intending to wake the plants up fast and put them to bed fast, so I just hung my far red emitter above the canopy so that all the plants could see it. It did seem to work though, in both respects... so I really don't know what difference it would make.

Now I have to figure out what Bruce Bugby means by adding 10% Far Red to your white LED's. Not sure if he means wattage or what i.e., ( 10% of 720 watts = 72 watts of Far Red) ?

 

[Emilya Green]

Now I have to figure out what Bruce Bugby means by adding 10% Far Red to your white LED's. Not sure if he means wattage or what i.e., ( 10% of 720 watts = 72 watts of Far Red) ?

I just used a halogen floodlamp... cost about $6 at the hardware store.