For me with my Diablos I still struggled with vpd, I moved my intake to the top of the room and dropped the exhaust to just below canopy height, all this really done was stir the air better and make air temps more stable.
I know there is ir coming from my boards cos I can feel it with my hand, however even with their radiant heat from big boards and the convection heat being pulled down towards the canopy, I still wasn’t happy with the vpd, leaf temperature was down, meaning I’d have to drop humidity significantly to maintain vpd OR add a couple fan heaters to blow hot air over the leaves.
My best results while following the vpd chart happen when the air temperature and leaf temperature are within 1c, due to the air temperature and not the leaf temperature being responsible for controlling the rh around the leaves.
I’m not saying I wouldn’t prefer to get the same performance from led as I get from a mix of the 2 but to do this would take a whole lot of tuning time and extra money. I do like the supplemental ir and uv bars from maxibright.
@Drasik what leds do you build? Do you have a site I can browse?
if you’re a beginner I would reccomend starting with led as it does iron out a lot of the beginners mistakes and make life much easier when maintaining environment, plants are also much easier to diagnose under white light.
I didn’t mean to come across as someone slating leds, their benefits are easy to see, the spectrum is amazing and the lack of heat produced from them due to their lower wattage is a godsend in the warmer months. And I’ll ditch the hps once I find a decent source of ir that doesn’t break the bank and can work out their ratios and positioning and wattage to a point where I can keep air temp and leaf temp quite close together.
I also must say though that cmh @ 3200k ish is where I’ve found the perfect spectrum and balance between air temp and leaf temp, I would go as far as to say that plants grown under warmish cmh grow faster, have tighter nodes, yield more and produce a higherquality flower compared to my hlg diablo 350r (new added blue spectrum).