This is more of a vent thread than a cry for help, but I’d welcome suggestions… just be aware that I’ve probably already heard them 
Once upon a time, I suddenly started getting yellowing/bleaching from the veins on new growth during veg. I’m still getting it. Furthermore, my vegging plants effectively aren’t drinking or growing at all.
My temps are fine (70-77f), my pH in and out seems within sane range, RH is on the low side (40%-50%) but not extreme (and still higher than it was in winter). As for soil, I’ve got a few different ones going trying to identify a reason for my problems. For all of them, drainage is good – maybe almost too good? When I feed/water, I get run-off in less than a minute, even with small quantities of water. For example, when I watered yesterday (after no watering for 8-12 days, depending on the plant), I only gave 250mL/ea for a 1-gallon pot, and probably about half of that just ran through into the drip tray.
So how did I get here?
Here’s my veg tent in April. Of note, the plants are reasonably healthy.
At this time, I was feeding at full strength every 3 days, 750mL for full-size plants and 500mL for the small ones. Exclusively using Happy Frog and GO box for nutes. In May/June, that stopped working
Here we are today. Space Candy in Roots Organic + 25% perlite:
Liquid nutrients for this one have been subjected to pH adjustment like I’d been doing all along. Maybe I’m driving soil pH up too far? Maybe I have a potassium build-up causing chaos in my soil? Let’s do a test:
Here’s Conspiracy Kush in lightly-amended Happy Frog, which I’ve been subjecting to nutrients without pH adjustment:
Last feeding was at 50% strength, July 27. Watered again on the 30th, and then waited 12 days to water again. It’s hard to tell if it’s worse or better than the Space Candy above. So, adjusting pH might be making things better, or at least doesn’t seem to make things worse.
Alright: maybe my nutes have gone bad. Maybe. But then I’d expect my bottle-fed girls in flower to have similar problems. Solution: don’t bottle-feed. Another test:
Here’s a Conspiracy Kush in Coast of Maine Stonington’s Blend soil + 25% perlite. I’m loving this soil for flower, by the way. Was loving it in veg, too, until a week go.
Oh look, weird yellowing like the bottle-fed girls. This plant has received only RO or distilled water, with a dash of CaMg+ for remineralization. Was growing better than the others, but has now slowed to a crawl and stopped drinking.
So maybe not the nutes, and maybe not the soil. I’m must be overwatering, or at least I need to get more air to my roots/soil so they dry out faster.
Sounds like a job for smart pots, right? Glad you suggested it:
My Wreckage mum in Ocean Forest + 25% perlite in a smart pot. That green growth isn’t actually new: it’s the inner branches that have been hidden by dying growth tips. I think I only went 9 days between watering with this one. In a smart pot. Nine days.
So maybe I’ve poisoned my plants. Maybe my RO filter is bunk and I’m killing off my soil microbes with tons of chloramine. Surely there’s no recovery for these. Except…
Conspiracy Kush, the mum (dad?) for the super soil plant above, and in the same soil mix as the super-bleached CK. But at this point, it’s kinda healthy?
This one has been living in my flower tent for 18 days to make extra sure it’s a male, and yeah. It is. Has been watered maybe every 6 days with RO + CaMg drops, spraying soil surface every-so-often with the same. That dying leaf in the lower-right is one of the old bleached leaves from the veg tent, because it was in as bad shape as everything else.
Soil seems to be capable of growing a plant, water does not seem to be poison. Good news, I guess, but doesn’t help me solve my veg tent problems.
So flower tent can sustain life: it has a 150w HPS + 315w CMH, and a good amount of airflow and ventilation. My veg tent has 150w LED + 96w T5s, no change in light/ventilation from When It Worked, however. Don’t think T5s on 18/6 would need to be replaced after 8 months, but guess I can give that a shot… and if that doesn’t work, I have no idea where to go from here.
Alright, vent complete. If someone can remove the gypsy curse from my veg box, it would be most appreciated.
Before I flipped the current batch to 12/12, I vegged for a month on 18/6 to nurse them back to health. This helped a lot, but does not make up for several weeks of unhealthy veg growth.
I’ve got backup beans for everything in there aside from the Wreckage, so would be sad but not the end of the world.
I’m starting some expensive seeds today, I was going to make a few changes to my soil mix, but maybe I should use exactly what worked last time.
You certainly have better intuition about when your plants need water, I’m still getting my green thumb back when it comes to fast-growing annuals.