Duration of UVB lights

[stellis0358]

I'm sure there is a thread that speaks to this but I couldn't find one. Simple question (or not I'm sure) what is the recommended duration of UVB lighting on my plants, and at what phase is recommended to start exposing plants to UVB?

 

[Creeperpark]

I'm sure there is a thread that speaks to this but I couldn't find one. Simple question (or not I'm sure) what is the recommended duration of UVB lighting on my plants, and at what phase is recommended to start exposing plants to UVB?

You have to be very careful and stay nearby to watch your plants until you get your UVB light dialed in. It's easy to bronze the leaves on some plant's using different substrates. Some grow's that lack adequate calcium can burn easily. That can happen today and not show up for a week or two.

As far as the duration part is concerned, plants' exposure time to UVB exposure lamps should be carefully controlled to avoid overexposure. This would include 1-2 hours per day during the vegetative stage, with exposure times gradually increasing as the plants move into the flowering stage. Google

 

[Rocket Soul]

Id say it depends on which uv light and distance aswell. When adding uvb you should have at least as much uva mixed in aswell

 

[420PyRoS]

Idk but i blast em right from seed with whatever most likely UVA comes with your typical chinese crap LED lights.

 

[Deleted user 4684842]

I use two 24W Reptisun T5 UVB lamps in my 4x6 tent and I run them 11/13. I think that's enough to simulate a "very high" UV index but I haven't measured the UV output so I could be mistaken. I've slightly burned a couple plants this way but that was intentional. I'm hoping that over time, by giving my Ethiopian hybrids as much UVB as they can take and selecting and breeding the best-adapted ones, I'll increase their THCV content. That's the hypothesis anyway. We'll see.

 

[Thegreengrower64]

I'm sure there is a thread that speaks to this but I couldn't find one. Simple question (or not I'm sure) what is the recommended duration of UVB lighting on my plants, and at what phase is recommended to start exposing plants to UVB?

I use the, 'solarcure flower power uvb bulbs'.
I generally start to use them at around 3-4 weeks before harvest. Starting off with just 30mins per day (on). Watching all the time to see how plants react. Then within a couple of days ( plants are all ok) ill raise to 60mins per day. The uvb bulbs are at a distance from canopy of approx 12 -18inches.

 

[Rocket Soul]

I use two 24W Reptisun T5 UVB lamps in my 4x6 tent and I run them 11/13. I think that's enough to simulate a "very high" UV index but I haven't measured the UV output so I could be mistaken. I've slightly burned a couple plants this way but that was intentional. I'm hoping that over time, by giving my Ethiopian hybrids as much UVB as they can take and selecting and breeding the best-adapted ones, I'll increase their THCV content. That's the hypothesis anyway. We'll see.

THCV = genetics and uvb; make sure you start out with genetics prone to thcv. We tried the Novarine from medical seeds which is bred to high thcv; all 7 seeds where duds and wouldnt get out of seedling state. Nowadays medical only sell novarine like an auto flower, my guess so they can control the genetics.

I wholly agree on breeding under uvb, our latests strains come from a breeder doing this but that bud is still in dry and cure so dont know how theyve turned out.

 

[Deleted user 4684842]

THCV = genetics and uvb; make sure you start out with genetics prone to thcv. We tried the Novarine from medical seeds which is bred to high thcv; all 7 seeds where duds and wouldnt get out of seedling state. Nowadays medical only sell novarine like an auto flower, my guess so they can control the genetics.

I wholly agree on breeding under uvb, our latests strains come from a breeder doing this but that bud is still in dry and cure so dont know how theyve turned out.

Yeah, Ethiopian has pretty consistently tested around 2-5% THCV, I think. I had poor results with THC Victory. So I'm breeding Ethiopian hybrids exclusively and the other strains I've selected to breed with were chosen based partially on how likely I think they might be to inherit the THCV trait from the Ethiopian. So Durban is an obvious choice. Emerald Fire OG Auto I chose because I saw a couple White Fire test around 1.5% THCV. Highland Thai I chose because I've seen a number of Blueberry hybrids test high for THCV and there's Highland Thai in Blueberry.