Leaf curling, unsure of cause.

Hey guys.

Things have been pretty smooth lately, but as I walk into week two or three of flower, I'm having some issues with leaves curling at the canopy level.

Now I know normally this is heat stress or light burn, but they're just as far as I've always kept them from the light, and my temp at canopy level is always 73-75 when lights are on, dropping to 66-68 or so when off. So I'm super confused. Any insight is appreciated.

Disregard discoloration. Was having pH issues until the most recent res change.

I'm in hydro, and my PPM is hovering around the 775 mark. Aeration of roots is good, check it every day. And roots are looking good in general.

So what's your professional opinion? Lower the heat?

Can't help with hydro but 75 really isn't that hot if the air is moving(fan).

Yeah, I have a fan right at canopy level. Maybe it is light burn, but that's really weird given that it's about a foot away, like it's always been. Only had one other time when it happened and that was when it was way too close back when it was a seedling.

It kinda looks like an Iron deficiency. And if they get darker on the tips and spread could be a cal-mag deficiency.

OregonMan said:

It kinda looks like an Iron deficiency.

Click to expand...

I'd be really surprised if so. The pH problem I've had was it dropping too low. So it was plenty in range to absorb it. Unless I just don't have enough in the res.

Wish there was a way to test for specifically that. I fixed the pH problem by lowering nutes, since PPM kept going up.

You could be right I'm still fairly a nooB. But judging from the copper looking specs on the bottom leaves in picture 1. And the curling upwards of the leaves it's one of those deficiencys.

Yeah, I undoubtedly had a calmag problem due to the rapid pH drops. That's why I cut back on the nutes. I was running 900+ and I mean pH was plummeting. Probably too fast for the plant to even absorb calmag. Talking 6.5 to 4.5 within a period of 8 hours.

And there was no root rot. PPM was just too high and kept rising, while she drank a ton of water.