UV light, adding to LED grow?

[DET—PDX]

Hey farmers,

Was reading an interesting article about how Marijuana is one of the subtropical species of plant which has adapted its own stress mechanism to UVB and UVA rays. I also am aware that most LEDs lack UV radiation, and even most metal halide lamps only emit about 10% of that wavelength. I am curious as to how one should add UV radiation to their grow if using LED’s?

I have heard of reptile lamps, but I have also read from another article that it makes sense to keep a UV light moving to avoid damaging plants. This could just be a company trying to sell their product, but it makes sense.

Do you think there is truth to keeping UV light moving? And what do you see as the best supplemental UV light that can be added to an LED grow? I am still researching and haven’t found a whole lot on supplemental UV lighting.

 

[Aroxol]

It’s legit and helps with trichrome production during flower, but there’s much better solutions than pet store reptile lamps. Go check out Rapid LED’s exotic booster board. That was too big for me to use, so I’m building a smaller version of that fits my flowering space, but UV def has an impact on increasing THC because the plants go to protect themselves from it (which in their world is developing more trichomes). Due to heat issues I’m going pretty deep into DIY LEDs, but there’s enough science behind UV at this point that I’d say if you have room you should def add in some UV because it’s cheap and will only help. Just be careful and limit your exposure.

 

[Emilya Green]

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.

 

[TorturedSoul]

One of my LED panels has an 18" 15-watt (or 15" 18-watt, I can't remember which) ReptiSun 10.0 bulb in the middle. It not only has its own power switch, it's actually set up with a separate power cord so that the user can run a different timer for it if they wish. I've only used the thing once, but when I did, I didn't have a second timer so I started manually turning the UV bulb on and off. But then I got lazy and just plugged both power cords into a power strip, plugged that into my timer, and ran the UV bulb whenever the panel was powered up. I didn't notice any ill effects (err... to the plants - I went from no liver spots on my hands/arms to about 23 during the course of the grow, which might be a coincidence, but maybe not as I didn't have sense enough to keep the grow room door closed, so was exposed to it for hours per day ). If I remember correctly, the manufacturer advised me to run it for a few hours per day, only in flower.

Seems like I read that the ReptiSun 10.0 is one of the strongest in terms of UV production. IF I remember correctly, I read something about it only being useful up to 20" away - but that was in regards to keeping one's reptiles healthy; I have no idea how that translates into a usable distance from the tops of the cannabis plants. That bulb is pooched and I need to order another one. I have been thinking about trying to get a 4' version, too, for when I'm using other lighting than the that LED panel (and because it would have a higher output).

As far as I know, unjacketed metal halide bulbs produce quite a bit of UV - that's why they are not approved for illuminating areas in which people are expected to be, unless the bulb is to be installed inside a "shielded" reflector (one that has a piece of glass between the bulb and the area to be lit.

 

[Aroxol]

I’ll give you guys updates on my current/ upcoming flower and would love to know about your firsthand knowledge as well. I’m going to be rocking far red initiators (put plants to sleep fast) as well as UV for enhanced frostiness. I’ve always been an HPS guy so I’m VERY curious how the high quality LEDs perform for yield and quality. Im vegging under an XML 350 I got for very cheap, and so far I’m wildly impressed by the results and healthiness of the plants (pot and vegetables) under high blue/ minimal red spectrum.

This is also an interesting article I read lately about HPS and LED you may enjoy.

The Effect of Light Spectrum on the Morphology and Cannabinoid Content of Cannabis sativa L.

 

[DET—PDX]

I’m getting good results under full spectrum cobs vero27 from timber, 3000k. I’ll be adding 1700k redish cobs for flower for certain. Maybe veg too for stretch and size. I reallu want to add a supplemental UV but so far all I can find are more LED’s with Uv built in. I love my timber, I’d like to find a way to rig a UV light up on it or at least attach it to it, probably will need a separate timer.
I also asked Dan, the company rep, about their UV light output, we’ll see what he says.

 

[Aroxol]

I’m getting good results under full spectrum cobs vero27 from timber, 3000k. I’ll be adding 1700k redish cobs for flower for certain. Maybe veg too for stretch and size. I reallu want to add a supplemental UV but so far all I can find are more LED’s with Uv built in. I love my timber, I’d like to find a way to rig a UV light up on it or at least attach it to it, probably will need a separate timer.
I also asked Dan, the company rep, about their UV light output, we’ll see what he says.

Heard great things about Timber, seem like awesome lights. Depending on his thoughts, their roadmap, and your interest in DIY stuff, seriously check out the solderless COBs as I think they’re probably better quality than anything prebuilt and much lower cost. Could be a stop gap solution until/ if Timber bakes them into your existing light. I’m going to be running this mix in a 2.5 x 2.5 x 4 flowering chamber, curious to see how it does.

-3x ChilledLogic 100w pucks (3000 and 630nm)
-2x 730nm Far Red Initiator Pucks
-5x 390-400nm UVA Cobs
-5x 840-870nm IR Cobs

 

[TorturedSoul]

I reallu want to add a supplemental UV but so far all I can find are more LED’s with Uv built in. I love my timber, I’d like to find a way to rig a UV light up on it or at least attach it to it

Probably end up being cheaper to simply add a separate fixture (or more than one, if your grow space is large enough) than trying to "bake it in" to an LED setup. I'd go the (high quality) reptile bulb route.

UV supplementation is not going to increase one's yield, only affect the quality of it. I assume everyone knows this, but figured I'd mention it just in case.

I’m going to be rocking far red initiators

Member Icemud has done a journal using such things. You might be interested in reading it. Should be able to find it by doing a search in the Completed Journals section for threads started by him. It has been a while, but IF I remember correctly, he wasn't greatly impressed by them (although my memory might be faulty on this). If you look and are unable to find the journal I'm referring to, let me know and I'll track it down for you. He has done LOTS of testing with lots of different brands/models/technologies where LED grow lighting is concerned.

By the way, I couldn't get that article (that you posted the link to) to load. After a lengthy delay, the website pooched on me and spat out some kind of error code (I didn't pay a lot of attention, but it wasn't a 404 error). I don't suppose you have an alternate source handy for it?

 

[Aroxol]

Probably end up being cheaper to simply add a separate fixture (or more than one, if your grow space is large enough) than trying to "bake it in" to an LED setup. I'd go the (high quality) reptile bulb route.

UV supplementation is not going to increase one's yield, only affect the quality of it. I assume everyone knows this, but figured I'd mention it just in case.



Member Icemud has done a journal using such things. You might be interested in reading it. Should be able to find it by doing a search in the Completed Journals section for threads started by him. It has been a while, but IF I remember correctly, he wasn't greatly impressed by them (although my memory might be faulty on this). If you look and are unable to find the journal I'm referring to, let me know and I'll track it down for you. He has done LOTS of testing with lots of different brands/models/technologies where LED grow lighting is concerned.

By the way, I couldn't get that article (that you posted the link to) to load. After a lengthy delay, the website pooched on me and spat out some kind of error code (I didn't pay a lot of attention, but it wasn't a 404 error). I don't suppose you have an alternate source handy for it?

Oh nice, I’ll for sure check out his stuff then, thanks. In terms of far red, my use of that is VERY specific - It will be run for 15 mins at end of 12 hour light cycle to put plants to sleep quickly. That’s it. UVA/IR also very limited and specific for trichrome reaction. For me the goal is trying new things, learning, and getting cleanest/ best quality I can, not too focused on crazy yields or quantity.

Try this link: (PDF) The Effect of Light Spectrum on the Morphology and Cannabinoid Content of Cannabis sativa L.

 

[TorturedSoul]

Yeah, I think that was his goal, too. Maybe, ultimately, to see if he could shorten the lights-off period for photoperiodic plants with no ill effects. It's past my bedtime and I'm fading badly, so I can't swear to it.

Thanks for the alternate link! I was even able to download the article without having to jump through any hoops first. I'll save it until I'm awake, then read it, lol.

For me the goal is trying new things, learning, and getting cleanest/ best quality I can, not too focused on crazy yields or quantity.

I can understand - and tend to agree with - that attitude. But the thought just occurred to me that, when I was chasing yields... The overall quality of the harvest seemed to be higher. I assume because I was attending to every little thing instead of getting lazy and thinking, "Ah, well, I'm not trying to grow {amount}." Just something to think about.

 

[Aroxol]

Yeah, I think that was his goal, too. Maybe, ultimately, to see if he could shorten the lights-off period for photoperiodic plants with no ill effects. It's past my bedtime and I'm fading badly, so I can't swear to it.

Thanks for the alternate link! I was even able to download the article without having to jump through any hoops first. I'll save it until I'm awake, then read it, lol.



I can understand - and tend to agree with - that attitude. But the thought just occurred to me that, when I was chasing yields... The overall quality of the harvest seemed to be higher. I assume because I was attending to every little thing instead of getting lazy and thinking, "Ah, well, I'm not trying to grow {amount}." Just something to think about.

Lol I’ve got way too much time and money involved to get lazy.

Edit 1: And just to clarify, I’m all about getting whatever high quality yield I can out of a light, but I’m dealing with LEDs and limited space. When I think of quantity and heavy yields, I’m talking about the ppl running lines of 1K DE HPS getting 3-4/ light. Can’t happen in my world, that’s all I mean.

 

[Mars Hydro]

Usually LEDs lack the uv lights, but add the white spectrum for compensation, since the white lights are the full spectrum lights. Also I heard to add T5 to add uv , and t5 is not expensive .

 

[DET—PDX]

Usually LEDs lack the uv lights, but add the white spectrum for compensation, since the white lights are the full spectrum lights. Also I heard to add T5 to add uv , and t5 is not expensive .

Metal halides do a marginal job but I’m looking for that 30% increase in trichomes. I found specific UV tube lights from a company called solacure and they’re skinny enough to mount right onto my timber. Problem... solved. Couldn’t be happier.

 

[Advocate420]

I’ve tried raising this subject before, finally glad to see it again!
UV lighting thread

T5 bulbs can be used to add UV light no problem. I’m experimenting with the FS+UV because the horticultural UV bulbs are too powerful for my purpose. I was cooking plants with less than an hour exposure. Remember UV is radiation. Protect yourself. I ended up in the emergency room with flash burn to my eyes, a figging welding injury.
Been playing with ideas for over a year and the ones using it are still sitting back I suspect

 

[Emilya Green]

We were not convinced in our early experiments that more than an hour or so of UV light each day was desirable. It seemed to us that there was a diminishing return after that point... UV is just too powerful. I am curious how this full spectrum LED with just one UV emitter will do.. it has to be a lot less UV than we were using.

 

[Advocate420]

We were not convinced in our early experiments that more than an hour or so of UV light each day was desirable. It seemed to us that there was a diminishing return after that point... UV is just too powerful. I am curious how this full spectrum LED with just one UV emitter will do.. it has to be a lot less UV than we were using.

I just got an LED bar that has UV and IR diodes. I am going to give them a shot to add spectrum to my HPS

 

[DET—PDX]

I just got an LED bar that has UV and IR diodes. I am going to give them a shot to add spectrum to my HPS

Yeah let me know how UV goes for you. I think for next grow I’m just going to add some warmer, red 1700k light with 2 cobs one in each corner alonglside my angled timber rig which is 3500k.

 

[TorturedSoul]

We were not convinced in our early experiments that more than an hour or so of UV light each day was desirable. It seemed to us that there was a diminishing return after that point... UV is just too powerful.

I mean no disrespect here, but the above statement would have been more useful if you had explained which frequencies (and/or frequency range), wattage, or some other measurement. Otherwise... I used to do a lot of hunting back when my eyesight was up to it (these days, I do most of my hunting in the grocery store freezer and, therefore, make do with lower quality meat). So. Imagine for a moment that I was getting ready to go hunt squirrels, and called a friend to see if he wanted to come along with me. My friend (being an odd duck, my hypothetical friend) looked at the one firearm he owned - which happened to use .50BMG ammunition, lol - and replied, "No, a rifle is just too powerful to hunt squirrel with." Without knowing that his "a rifle" was a very specific one that might be best used (in the non-militaristic sense of the term) to hunt big game on a mountaintop whilst standing on a completely different mountaintop... I would have thought his generic statement to have been both silly and nonsensical - because it lacked context.

 

[Emilya Green]

sorry I can't be more specific... I didn't keep as good of records back then and most of what we did was DIY anyway. Didn't mean to offend by offering an unsubstantiated and undocumented opinion... what in the world was I thinking???

 

[TorturedSoul]

I wasn't offended (you'll find it's pretty hard to offend me).

Perhaps you missed that "I mean no disrespect here" part that I prefaced my previous post with?