Looks like you either a). overferted them or b) have a salt build up from the nutes you are using. Use plain water for a couple of waterings. If they are already 17 inches, you may want to repot and low stress train...LST. That is tying the main stalk down to expose more budsites to light. Then after the transplant seems to be okay, put them in flower. They can and probably will double if not triple in size once put into flower...
They look pretty good, and the browning doesn't seem to be that bad....


:jointsmile: Bree