UV Suppliment Lighting

I say go with UV regardless the technology used to emit it. I still use CFL reptile bulbs. They are not the most effecient but they work. Adding UV is the single most significant and cheapest thing you can do to increase the potency of your bud immediately, imo.

I'm an LED guy, but fluoro work well too, they put out a more full SPD than UV LED can currently produce, but I think LED is more effecient at providing UV than fluoro is at providing UV, but still not entirely sure on that. All UVB chips are only about ~1-2% efficient regardless the brand, but you don't need much of it, so it's offsetting. On the contrary UVA chips can be over 70% efficient and won't burn out after only a few thousand hours like the UVB chips will. The UVB fluoros wear off over time as well, similar to the UVB chips.

It's a bit of a personal choice what technology or option you choose. Price, know how, grow room dimensions, etc. If you want an easy solution to start out with, I'd say look at the arcadia 6% UVB's or 26W UV CFLs. @Or_Gro is using 6% Arcadias 12hrs/day with no adverse effects. As a rule of thumb the lower the WV the emmission the higher the risk of damage. Reptile bulbs only get down to about 300nm, the Agromax's and some of the others have emissions below 290nm and as a result need to be monitored more carefully. I'd run 2 reptile tubes for your space, or 4 reptile CFLs. Not basking IR lamps, but UV lamps. I use (4) 26W UVB150's (CFL) in a 4×4 cause they were cheap ($9/shipped) and work well. I didn't ramp up my doseage, the first time I just added all 4 of them during bloom at 12hrs/day, now I use all the time (veg & bloom). If the SPD went below 300nm I doubt I'd be able to do that.

interessting to read your thoughts.
i somehow fear that the arcadias fixtures are a bit bulky in the end.
it isnt urgent for me, so i will evaluate more.

atm reading about these epiled uv leds in auquaristic forums.
Theyre avaiable from 365-420nm, you probably know.
Maybe mix some uvb with uva and build some kind of addon strip with them.
According your info, i wont need much UVA leds then to get the desired 1:3- 1:6 UVB to UVA ratio?
You really have some knowledge

Driven low i think i could achieve a usable spread, better then with cfl and these uv leds are dam cheap.
I would be willing to spend more, but at this point i only want to toy arround a bit.
Just my 2 cent so far.

ChiefRunningPhist said:

I say go with UV regardless the technology used to emit it. I still use CFL reptile bulbs. They are not the most effecient but they work. Adding UV is the single most significant and cheapest thing you can add to up your potency immediately, imo.

I'm an LED guy, but fluoro work well too, they put out a more full SPD than UV LED can currently produce, but I think LED is more effecient at providing UV than fluoro is at providing UV, but still not entirely sure on that. All UVB chips are only about ~1-2% efficient regardless the brand, but you don't need much of it, so it's offsetting. On the contrary UVA chips can be over 70% efficient and won't burn out after only a few thousand hours like the UVB chips will. The UVB fluoros wear off over time as well, similar to the UVB chips.

It's a bit of a personal choice what technology or option you choose. Price, know how, grow room dimensions, etc. If you want an easy solution to start out with, I'd say look at the arcadia 6% UVB's or 26W UV CFLs. @Or_Gro is using 6% Arcadias 12hrs/day with no adverse effects. As a rule of thumb the lower the WV the emmission the higher the risk of damage. Reptile bulbs only get down to about 300nm, the Agromax's and some of the others have emissions below 290nm and as a result need to be monitored more carefully. I'd run 2 reptile tubes for your space, or 4 reptile CFLs. Not basking IR lamps, but UV lamps. I use (4) 26W UVB150's (CFL) in a 4×4 cause they were cheap ($9/shipped) and work well. I didn't ramp up my doseage, the first time I just added all 4 of them during bloom at 12hrs/day, now I use all the time (veg & bloom). If the SPD went below 300nm I doubt I'd be able to do that.

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So you suggest using the 6% over the 12%? I was talking with @Randomblame a while back and he suggested me to go with the 12% @4hrs during lights on @12" distance from canopy. What's the benefit of going with the 6%? I'm just just asking because I'm not that well educated regarding this subject.Thanks!

cobshopgrow said:

interessting to read your thoughts.
i somehow fear that the arcadias fixtures are a bit bulky in the end.
it isnt urgent for me, so i will evaluate more.

atm reading about these epiled uv leds in auquaristic forums.
Theyre avaiable from 365-420nm, you probably know.
Maybe mix some uvb with uva and build some kind of addon strip with them.
According your info, i wont need much UVA leds then to get the desired 1:3- 1:6 UVB to UVA ratio?
You really have some knowledge

Driven low i think i could achieve a usable spread, better then with cfl and these uv leds are dam cheap.
I would be willing to spend more, but at this point i only want to toy arround a bit.
Just my 2 cent so far.

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Ya I'd go cheap on the UVB chips, but I'd personally spend the coin for the best UVAs I can find. All the UVBs will burn out after awhile, and they all are around 1.5% efficient, so I'd just go cheap there. You could definitely go epistar for the UVAs, as I think brand or effeciency is preferential to your goals.

If the beam angle on the UV chips is the same you should be able to calculate your ratio like you were describing, though you want to compare watts of output not watts of input.

thanks for the info, very helpfull.
On the quick i just found a cree with 395-400nm, a bit on the high side for UBA but could do the trick.
Will see, havent even deicded for a driver.
This will supplement 320W 3000k 80cri light, may i ask what you would roughly suggest in watts/percentage maybe 5% 16W?

KasparGrower said:

So you suggest using the 6% over the 12%? I was talking with @Randomblame a while back and he suggested me to go with the 12% @4hrs during lights on @12" distance from canopy. What's the benefit of going with the 6%? I'm just just asking because I'm not that well educated regarding this subject.Thanks!

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Haha that will work too. 12% will provide 2× the UVB as 6% (duh lol), so you'd need less. According to @Or_Gro he's using 6%er's for all day. To me that's an easier way to go than setting up seperate timers ect. On the other hand, the bulbs will probably last longer being used less, and you'd use less enegy, so it'd have an added benefit of being more effecient. If your timer malfunctioned though and the lamp was intense and kept on all day your plants could be fried. Agromax is the bulb that @Randomblame was using last I spoke with him, and that bulb is probably the most effecient fluoro for UVB, but I think he was upset with how intense they were and had issues with them damaging plants at only 3× at 20min a day (I think, but can't remember exactly). The ratio was also not to his liking, too much UVB for the amount of UVA he hypothesized.

Yes! that was the problem with the Agromax... The advantage I see in having a timer is also to ramp up the UV dosage for the first week or two,starting with 1hr a day to 4hrs a day.

ChiefRunningPhist said:

Haha that will work too. 12% will provide 2× the UVB as 6% (duh lol), so you'd need less. According to @Or_Gro he's using 6%er's for all day. To me that's an easier way to go than setting up seperate timers ect. On the other hand, the bulbs will probably last longer being used less, and you'd use less enegy, so it'd have an added benefit of being more effecient. If your timer malfunctioned though and the lamp was intense and kept on all day your plants could be fried. Agromax is the bulb that @Randomblame was using last I spoke with him, and that bulb is probably the most effecient fluoro for UVB, but I think he was upset with how intense they were and had issues with them damaging plants at only 3× at 20min a day (I think, but can't remember exactly). The ratio was also not to his liking, too much UVB for the amount of UVA he hypothesized.

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I digitized a generic solar SPD and found that UV makes up about 7-8% of total solar emmision from 800nm and down. I'd shoot for 8% max of total UVA, and then dose the amount UVB by UVI. @nachooo is having success with only 60mW of 285nm for 2.5hrs/day in 1m2 area. I propose multiplying mW/ft2 of 285nm by 1.29 to achieve an equivalent UVI. UVI is weighted towards the WV range that is most active in stimulating the UVR8 molecule.

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thanks for the brainfood.
So far i am having problems finding options for leds below 365nm.

cobshopgrow said:

thanks for the brainfood.
So far i am having problems finding options for leds below 365nm.

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Ya that's one of the issues with UV LED, they are pretty much non existent from 330nm-355nm. In this WV range fluoros hold the upper hand, though I've not seen any photoreceptor absorption peaks in this range so I'm hypothesizing it's less than nessecary to have these UVA WV's, but really can't say for certain.

all not so easy, i went the simple route and ordered 4x 13W cheapo reptile lights and will see how this works.

Digikey has diodes on stars that go down 275nm.
Migro apparently tested some uvb and uva led. Uva led results were solid. Uvb led were not putting out anything he could measure. No idea which diodes he tested.

Seoul Viosys, RayVio, LG, Nichia, are all legit. Other than that I'm not sure. Idk the chips or the meter that Migro used. Some of the chips I've seen only push 1mW total, depending on the spectral responsitivity of the sensor and the precision of the meter you may not read much if testing only 1 or 2 of those.

275nm seems a bit low of a target WV, here's a UVR8 action (dotted) & absorption (solid). The lower WV you go the higher risk for cellular damage.

I definitely would not go lower than 280nm, they do have the brands you mention cut off at 280nm at digikey. They are just way too expensive for me.

Warpedpassage said:

I definitely would not go lower than 280nm, they do have the brands you mention cut off at 280nm at digikey. They are just way too expensive for me.

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You can buy 4 stars seoul viosys 285nm for 80 $.. They cover a square meter if drived at 150 ma which is 60 mw..or driven at 100 ma give 40 mw which is not bad at all.. Driver should be about 10 $

nachooo said:

You can buy 4 stars seoul viosys 285nm for 80 $.. They cover a square meter if drived at 150 ma which is 60 mw..or driven at 100 ma give 40 mw which is not bad at all.. Driver should be about 10 $

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Thats more manageable, when i was pricing it, i was looking to do one diode per sq ft.

Warpedpassage said:

Thats more manageable, when i was pricing it, i was looking to do one diode per sq ft.

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Yes...I overdrive them a little until 150 ma..And seems to work ok..If you use them only 3 hours a day about one month and a half per crop..should last some years....I am using them in veg also cause I want to simulate the sun since the start...but is not necesary

I've heard it is best to alternate the UV, one day on, one day off to prevent plants producing UV resistant pigments... I think It was Dr Bugbee.

ANC said:

I've heard it is best to alternate the UV, one day on, one day off to prevent plants producing UV resistant pigments... I think It was Dr Bugbee.

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Those "pigments" would be THC

I do UV thru out, seedling, veg, flower and if you're gonna use it you should too