It depends. If youve been adding nutes, how much, I add bloom nutes and I use 1/4 what it suggests and iv never over nuted just b.c this is my first grow so I havnt attempted to add more. I wouldnt worry too much about it, if all your plants start getting really deep green and the tips and edges of a lot start to yellow Id say lay off the nutes, but its normal, they get old and arnt needed, I just tug a lil on them and if they come off they come off, no biggie.