Update from early week 4 of veg BBnC (2 soil 1 coco):
Girls have definitely been through some stress, but they just keep wanting to live despite my screw ups. Everything had been progressing along explosively, but I was pushing a bit too hard on the plants. When I was trying to dial in my PPFD (with a $15 lux meter, the conversion based on HLG specs, etc etc etc), I (once again) overestimated the power of these quantum boards. God. Dammit.
Leaves started to wilt and displaying signs of N toxicity. Basically, let me just sum it up to this.... doing DIY with QB’s, research needs to be done on electrical physics. I can confirm, in veg, plants do NOT need 2x HLG QB260 kits in a 4x4, even at 30” and half power. Also, wattage is a garbage metric for evaluating/calculating PPFD. Annnddd finally, if you’re gonna screw with some of the most photosynthetically efficient lights out there, you really need a proper quantum meter. It’s really easy to go from optimal to excess with these lights.
Well, my SQ-520 quantum meter comes in this week, but in the interim, I’ve concluded that the drivers in this kit paired with only 2x 288 boards/kit are extremely goddamned efficient. Literally, you cannot decrease the output from the lamps enough to be able to run more than 1 in a 4x4 for veg. Even at 30-40 inches. I have just completely turned off my other fixture until flower. 1 QB260 kit at 30” is plenty to veg with.
At any rate, after causing a massively high VPD, extreme drought, and jamming PAR down these plants’ throats, I started to experience straight up wilting. Not dropping, but dry, papery, curling type wilting (+N toxicity - both in soil and in coco, telling me this was environmental). I probably could have pushed if I kept the VPD within range, but temps got to 77-81 with RH in the high 40’s-low 50’s while being massively over lit. Moral? QBs = don’t fux with these without a really good idea of basic electrical physics and the properties of light. Watts = useless measurement. We need to evaluate in volts/amps, and do some good solid par mapping.
Anyway, I gave the girls a pretty aggressive pruning, including snipping (removing only the damaged parts) leaves that had more than 50% viable tissue to preserve their ability to photosynthesize temporarily as new and healthy leaves refill the canopy. All in all, after fixing the light intensity/distance/VPD issues, the ladies are starting to rapidly grow again, with all new leaves looking healthy. This issue affected my Strawberry Nuggets Auto (Mephisto) seedlings as well, though I was able to intervene early and correct the environmental problems and subsequent nutrient issues (calcium def) as well. Everything in the tent has resumed healthy growth, and I’ll be making use of my Quantum Meter and humidity controllers from here out. Anyway, here’s some pics. Other than that small setback, training is going well and these ladies are going to make a LOT of colas.
Got myself a nice little seed stash too... through I need some more Useful’s! If I can abuse other strains half as much as I can these, I’m sure they all have wonderful genetics.