Nute burn or light stress

Hey there HappyDays, you got magnesium and calcium deficiency, you can tell from the rust spots affecting the top leafs as well as the discoloration on the serrated edges of the leafs. But you're actually right, this is all due to the "light stress". that's because plants need more Mg and Ca to regulate photosynthesis, more photosynthesis more calmag is needed. The problem is that the plant's absorption efficiency through the roots is something like 20% so the plant simply cant absorb enough calmag through it's roots. To treat this problem, either reduce your light cycle as much as you're comfortable with to treat the root cause. Or make a calmag spray something like 1mL - 1.5mL /L and spray twice a week to treat the symptoms. That's because absorption efficiency through the leafs is 80% so much better than the roots. Hope this helps growmie ! 🚀

Inproper ph leads to plants not being able to absorv the nuts properly and starts to eat itself. And the heatlhier your plant is the more light it can handle.

I got the exactly same problem with my Blue Dreams , and this happen always at my sativas, I run organic too , did u set up the pH ? Cause I am not I give them water with like 8 pH but this always works for me cause of the organic feeding and my earth got a pH of 6,2-6,5 . I thinking about lightstress too this can make a lockout but I dont know . I need that help also . This always starts at the Top of the plants the bottom seems to be healthy.

Did you foliar feed within the last week maybe 2? And possibly not turn the light down enough.... that's what it resembles to me. If not that, I would check my rum off and if the #s are high, adjust my feed accordingly. But it doesn't look to be light burn too me.