Lighting What is the optimal way to use UVA supplementation with autoflowers?

[BII]

I just purchased the Mars UR45 UVA/IR supplemental strip light, which is rather similar to most other UVA/IR LED lights. I have seen greatly divergent recommendations for UVA use. Some (out on the Internet) recommend ramping up to several hours/day in later bloom (what I am starting to do); some just run all the time (along with the main lights). Some photo growers report success with 12/12 and some auto growers report success running continuously. A problem is that most recommendations and feedback reports are with photosensitive plants.

What is the optimal way to use UVA supplementation with autoflowers? How many hours/day, starting when, etc.?

 

[JP1]

Haven't seen anything specific with autos and uva yet. But I run my lights 20/4 and my uva for the middle 12 hours from the start. I've noticed better flavor and some minor foxtailing at the end on about 50-75% of the plants since using it. Nothing noticable in weight

 

[DCLXVI]

This article is about the fluorescent UV bulb they make but it's a bit useful.
Some info here:

New Grow Hack Increases THC Levels By 28% – AgroMax

 

[Drownomatic]

I use their PureUV bulbs.

3 15 minute blasts from about 4 ft above the canopy.

This is easily enough UV to give a serious skin burn if you forget you are under it and it comes on. By the time you feel your skin frying its already a 2nd degree burn, so pay attention, or use a lockout when you go into your grow room.

 

[Badfinger]

I have the same lights, I run 30 minutes, 4 times a day evenly spaced over my 18 hours. Due to the configuration of these lights, I havent used the IR feature. It seems the designers think your going to sit in a chair all day long and manually operate them, dumb!

 

[Mañ'O'Green]

Do not confuse UVA with UVB. I think the only consideration as to how long to run the UVA depends on the price of your power. There is some point when it may no longer be cost effective. UVA will bump up the terpene profile and I love my terps so I run the UVA from mid veg to harvest 18/6. It probably is more than needed but it won't harm to have too much. UVB on the other hand, can burn a plant (you too) I run it for 2 - 30 minute sessions mid day the last two or three weeks prior to harvest. Bruce Bugbee says there is no measurable increase in THC but I find there is an entourage effect that makes my weed better. YMMV

 

[BII]

Do not confuse UVA with UVB. I think the only consideration as to how long to run the UVA depends on the price of your power. There is some point when it may no longer be cost effective. UVA will bump up the terpene profile and I love my terps so I run the UVA from mid veg to harvest 18/6. It probably is more than needed but it won't harm to have too much. UVB on the other hand, can burn a plant (you too) I run it for 2 - 30 minute sessions mid day the last two or three weeks prior to harvest. Bruce Bugbee says there is no measurable increase in THC but I find there is an entourage effect that makes my weed better. YMMV

Thank you very much. I recall your prior comments on UVA as one of the factors encouraging me to buy the fixture.

My Mars unit and seemingly most of the other basic models also come with IR. Do you supplement with IR, and what is a good regimen?

 

[Mañ'O'Green]

Thank you very much. I recall your prior comments on UVA as one of the factors encouraging me to buy the fixture.

My Mars unit and seemingly most of the other basic models also come with IR. Do you supplement with IR, and what is a good regimen?

No IR is mainly heat, maybe a tiny bit of red >700nm but not needed IMPO. I already battle heat.

 

[BII]

No IR is mainly heat, maybe a tiny bit of red >700nm but not needed IMPO. I already battle heat.

This confirms my presumption that additional IR is not needed. It was cheaper to get a combination UVA/IR 2-strip unit vs. a single-strip UVA-alone unit.

I presume the >700 red you cite is provided by the small portion of red LEDs included now on most LED lights, such as on my HLG rSpec and SpiderFarmer quantum boards.

 

[Drownomatic]

I feel like one vendor puts something on a light and the others follow without testing themselves if helps.