Theres not a lot of info around about the strength of these QB's and them burning plants. If you search around, most of the threads you find on here about this will be me bringing it up. Its definitely a problem. It can be fixed though because I've done it and im crushing it with high intensity quantum boards and low ceilings now. Im sure one of my solutions or maybe a combo of them will be your solution as well. I still won't recommend quantum boards though and ill be switching to bar style LED's next time I buy lights.
you make some very valid points.
what I noted from bar style racks is they typically are either just white light diode or you cant really go close up with them otherwise the rare 660nm etc supp doesnt really mix into the light recipe
that chinese manuf. solveemd that problem IMO (also his lenses to produce a controlled fraction of diffuse light is remniscient of the natural skylight outdoors)
Probably because outside theyre exposed to UVA/B from day one.
I start seedlings, veg and flower my plants under 2 Solacure 4ft Flower Power bulbs in each 4 x 4 area, and also start seedlings under a 1000w Hortilux HPS, and a Gavita 1700e. All 3 at 24 inches from canopy. I use the HPS bulbs from seedling-flowering. I use the UVA/B for 4 hours a day at 24in from seedling-flowering. I will use a longer UVA/B scheme if I use a 1150w DE Gavita DE bulb as they have to be run at 36in-40in or they will fry because of infrared.
Using a Lumen to PPF Calculator at 145,000 lumens the 1000w Hortilux puts out roughly 1881umol at 2000k The Hortilux is 2100k. Ive never had a plant burn doing this. I also have tremendous fresh air flow. My temps are between 78f-84f.
interesting report Sir. what's your light schedule? well, my take on that would be (a) initial accustomization to full spectrum + high luminosity and (b) HPS contains partially some colours (oranget, bit green) that doesnt create that much heatstress on initial tissue than blue & red (high absorption)
the HPS IR rather shines through so creates heat homogenously
though I dont wanna equate high temps with high irradiance, but certainly these things influence one another
I'm sorry I didnt quite catch that reasoning:
I will use a longer UVA/B scheme if I use a 1150w DE Gavita DE bulb as they have to be run at 36in-40in
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that said, the plant response to UVA/B may also be helpful vs strong irradiance photodamage - it has even been shown to ve effective to alleviate some drought stress ( & vice versa)