Ive found that over watering causes 95% of the problems ive seen. But being rootbound is bad too your pots look too small bro i would say pot em up and only water when they wilt. Good luck bro let us know.
Im gonna say over water for sure man i had a few like that. They have nute lock out. My two cents bro. Mine never came back :( i wish you luck though man.
From what i found growing indoors requires very little watering, over watering causes nute lockout no matter how much ferts and crap you put in it wont help. Wait till your plants wilt and look like they are gonna die before you water them. Doesnt matter if the top couple inchs are dry. Try it...
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