dude its not a ph issue, even very very dry environments would do that to it. im tellin you look up leaf margin cupping or rolling. your plant is trying to breathe. if it is a grow box, or any set up for that matter with poor ventilation and high heat it could most certainly happen over night. i would IMHO (but experience driven) check drainage, temps, and ventilation. i dont know of anything other then those 3 things that would make your margins curl up so radically. hope you make the "right" choice. for your girls sake. GL man. check humidity as well if you have a meter. should be like 40-50 60 tops.