UVB Lighting Schedule: How long is too long?

Hey Gang,

Wondering how long to run a UVB. I’ve been running a California light systems UVB for 2 hours a day 24” above the canopy for the last 9 days. Hard to tell if it’s doing anything. I can’t find much direction online. I am 1 or 2 weeks away from harvest and considering adding another two hours a day but I don’t want to torch her.

How long is too long?

Thanks in advance!

It’s a shame someone with more experience of this hasn’t answered this thread.
I have just recently got a UVA/UVB light to add to my set up, so I’ve been consuming quite a bit of content about them. I think you’ll be okay going up to 4 hours and possibly more, I recall a YouTube video the otherday saying he runs them for 4 hours a day, but obviously that depends on the dose and the set up being the same etc… I’d probably say if you’re not seeing any detrimental effects at the current dose, then try taking it up incrementally and see how it goes?
I’m not sure you’ll ‘see’ any results anyway, some have commented that they visibly get more frost, but even if it just improves terpenes and flavour, it’s worth it and those are obviously things you can’t see.
Good luck.
I’d be interested to hear how you got on.

peace

H

it all depends on the source of UVB. I don't run clw and I'm not one to assume. I can give my experiences with 4x4ft agromax uva and 1x4ft agromax uvb. My thoughts.. Always supplement with UVA and at 1-2weeks out it doesn't matter what you do to the leaves.. so crank UVB until you see burn. Leaves will go first (buds should be heavy with trics at this point) so thats what you look at and then back off a little in height or frequency of bursts. You'll know your basic limits for the next cycle. (some cultivars handle it better) As far as frost.. most definitely did something for the recent cultivars I've tried with it so far. pics, pics Not sure if the stalks are longer or something but seems more dense to me.

If you go overboard with harsh radiation a drop in total terpenes is to be expected

You need slow acclimation with UVB way more early
And a genetic that responds positive of it - a chemotype I high-THC no-CBD "sativa"
mild UVA for photorepair
And the UVB only every other day or only every 3 days