I'm not even sure what the problem really is. To me it looks like a magnesium deficiency and I've already ordered some Epsom salt. I grow in coco and under LED light. I water every 3-4 days (when the pot feels light) with plenty of drainage (30%). I give nutrients every watering (Canna Coco) and I haven't flushed once since I don't really see the need when watering nutrients with enough drainage every time (maybe I'm wrong). The new growth looks pretty good to me, not every leaf is affected, just some of them and they got worse over the days. But no new leaves affected I think. What do you guys say? Switched to flowering on the 28th of July, Sensi Seeds Super Skunk \nEdit: It seems that only leaves on this certain height have this deficiency. The older and newer leaves seem fine http://i.imgur.com/H2aeGWa.jpg
Oh yea i got it now lol your writing is all dark on my tapatalk app. How has their feeding been? And whats the ph of the run off? Maybe a nutrient lockout (magnesium) instead of defeciency
The ph of the run off is exactly the same as when I prepare a solution and feed. (6.2). So I guess no lockout, just plain deficiency? I feed them every 3-4 days with around 3 liters of tap water (it's good here) I prepare a bucket with 4 liters of water and put around 8ml of A and 8ml of B in. No nute burn, no other deficiencies. Only the magnesium seems to miss.
Have you tryed a lower nutrient ph? Try it at 5.8 for a few feeds. Everything else seems pretty much spot on.
Just try em a bit lower lol if it gets worse higher it back to 6.2. Worst case try and spray em with epsom salts in warm water. Has it gotten worse since you posted?
I should've probably mentioned that I have no pure coco but coco+perlite (50/50). When I made this post I didn't think that it mattered. Can I feed my plants the magnesium by spraying it with epsom salts in warm water? Someone told me it's not a good idea to mix epsom salts and coco.
Yea you want to foliar feed them epsom salts spray the underside of the leaves thats where the stomatas are
Been using coco for years and have to use 1/8-1/4 tsp Epson per gal for most of my strains. Some strains are Mg beasts. I dont like to spray my girls in flower if I dont have to. The old growth looks to have the problem, so that points to Mg or N, doesn't look like N to me. Your ph is 6.2 (coco 5.6-6.3) so ph shouldn't be an issue. I'v read also not to use Epson in coco but I never once had any issues, but have corrected many Mg def by supplementing Epson.