Next time you grow add worm castings about some 6 or more hanfulls of worm castings to a 3galons of soil. Worm castings can solve many problems, It stabilize the nutrients in soils, and worm castings by them selves is a light nutrient, Marijuana plant takes all nutrients from it pretty fast, that's why you has to add much of it, but don't overdose. Most of worm castings ph is 8, but that ain't so bad, if soils ph is 6. This year I grow outdoor again, and to a fev buckets I added the worm castings, those plants are healthy, green, not any problem, even the old leafs, that has to die is half dead, but still green (except Powdery Mildew <-it causes the heat and high humidity, but that ain't that bad, cause I'ill put those plants in H2O2 right before trimming) Other plants, that hasn't those worm shit, now is in a poor condition, most of the leafs are yellow, rest of the leafs are light green. To a plants I add a rain water with organic nutrients ( rain water was clean), so I guess the worm castings has pretty much nitrogen too.