I’ve started noticing some yellowing at the tips of some newer fan leaves.
I assume it’s either from too much light or too much nutrients. How can I tell which?
It’s happening on both Bad Girl plants in the tent. They are in early veg and being trained for mainline/manifold… in Octopots.
Light is at 18" and 600 PPFD.
Nutrient strength is at 590 ppm, pH 5.8 (Athena Blended nutrients).
I’m going to be weirdly specific but that’s copper deficiency.
I only know because I had that same type of yellowing on the tips of the upper leaves that spreads towards the edges. As it advances the edges will burn more looking like potassium deficiency. The leaves will then turn a dark green to almost blue or purple
When I took a soil test from Logan Labs copper was one of the micronutrients I was low on and the Soil Doctor guy recommended I balance my micronutrients.
I was pulling my hair out for years trying to figure that one out.
What pH does your run off water have?
In autopots, I’ve had a similar issue once. My run off came out with a unbalanced pH and high EC, giving me the tell tell sign of salt build up in the medium. After a flush until the run off had a stable pH and low EC, it bounced back very fast.
Pz 
I’m also having this problem too, however I don’t believe my problem to be iron because it’s mobile and iron is not, I’m having the same issues however I’m also getting burns on the tips and margins, I’m thinking i might have given a high dose of K when using seaweed extract.
With Octopots, there is no run off, and no top watering. The plant draws water from the reservoir. The reservoirs have remained stable at pH 5.8 and 590ppm. NOTE: I did have pH 6.2, 970ppm water in them for a few days last week before adjusting.
Sounds like you went a bit hot for a couple days is all
Yeah, but the medium is still moist and salts can still build up. You should check run off as a test for checking for salt build ups.
Pz
The Athena Bloom B nutrient accounts for nearly half of my 590ppm and lists “Copper EDTA” as an ingredient.
OK I understand, but the Octopot method is very specific about NEVER top watering. I’m not sure if it would be wise to top water flush with RO.
No top watering when bottom feeding , as this pushes the upper salt tideline back into the lower root zone upsetting ph ec and nute ratio etc
Plus you will upset the perfect gradient from wet to dry within pot
I checked my Gaia Green regiment and I’m definitely running excess in the iron department
Im with @Cory on this one.This plant got planted in some slightly hot soil and did the same thing.Little yellow tips but it straightened itself out and is doing well now.I think you had some extra Feed in the Res.She should be fine and snap back dont look too bad.Ive burned them up way worse and they still preformed .Mind you i paint my Pots with Microkote
I just want to point out that type of tip burning is very different than what OP has. That looks like actual nitrogen burn from too many nutes. It’s the tip only and then the tip starts to die back.
OP’s burn is fading that starts at the tip but progresses towards the perimeter of the leaves. It will look similar to a potassium deficiency except it happens at the top of the plant instead of the bottom. Let it get bad enough and the upper leaves straight up turn purple. Check out all the pretty flower pictures with fall colors people post on reddit. They all have extreme copper deficiency!!
I dunno, it’s kind of a unique type of burn.
But yeah, maybe he’s experiencing salt build up, lockout, PH issues, or maybe his cultivar is extra fussy. Who knows. I also run organic soil so maybe my experiences don’t directly translate.
My observation is based off of soil so take what i say with a grain of salt.Hes using octos and thats a whole different ball of wax im a soil geek and ive never really tried with anything related to hydro liquid nutrients growing so this could be one thing im thinking or a couple in tandem for all I know.From what i see with soil when one things out of whack otheres follow suit because of the deficiency throwing off the nutrient chart and becoming a combination of things.Its a delicate balance growing plants.With the little pockets in the leaf in that one pic id bet my budd @George might say phosphorus deficiency.Hes very good at coming up with possible issues and has a lot of good useful pictures and diagrams
Whats a potassium ?
Three things come to mind
copper maybe
Potassium possibly
Heat from the lights if I remember your at 600 watts .
Just something to check
500W AC Infinity EVO6… but it’s only at level 4, 18" (600 PPFD)
Hm, my soil test did also show I had very high sulfur levels.
@CrookedTooth Hey bud did not totally understand what media you are running. Typically call of action for any time PPM rise a flush is needed to start fresh on nutrition and substrate. Maybe just run 1 feeding cycle on water to flush substrate and resivor if I understood your grow well enough. Cheers !!!
