This is my first grow. It's northern lights. In 4th week of flowering and I'm getting these dark edges on some of my leaves. They are well fanned and it's not just leaves nearest the lights. Any help much appreciated.
alright guys break it up break it up. but yeah the plant is well fanned so i dont think it's heat stress. and magnesium deficiency looks different from other pics i've seen. any other ideas?
Thank you. After looking at that and a bit more research definitely looks like potassium deficiency. Going to get some sulphate of potash tomorrow. Will update with progress.