Could you be using miracle grow soil. Or some cheap nutrient release soil? If so get them out and in to something better! Looks like a few problems. I see p deffiency . Probably from salt build up locking it out. The yellowing and crisping of the leave really looks like typical crappy soil use. When I was new I used mg soil and ferts, I had to pull my crop early every time cause of the same symptoms your getting. Now I use a mix of fox farm ocean forest, perlite, and sunshine mix #4. If you want good bud it starts in the soil ! Sorry bout the rant. Yes you can save them! Soon though!