I believe this is rust and not a nute problem. There are nute co. that sell stuff too kill the rust that attacks MJ. Advanced nutrients is one.

good luck, just my pennies worth.:thumbsup:
jamessr Reviewed by jamessr on . Dark brown spots then dead leaf I have been watching these spots on my leaves for a while now. At first I thought it was because of my nutrient abuse when I tried to grow these in 3 different systems in the past month. Then I thought it was because I would sometimes splash water on the leaves and burn the plants but now I think I have a real issue. The spots are spreading to other plants and on growth after my learning curve issues. The leaves steadily grow more crusted with the spots, the leaves yellow and then they get Rating: 5