Drying help please

Little nervous about this harvest..about to cut em down and dry by have some pretty big buds and worried about mold .. I've never got it usaly run OG buds smaller yields but anyway was gonna dry in my bloom room is only place I can dry them. I can't afford to slow my next run down its ready to go right in so I have a big closet in there I want to use and my concern is over crowding and temps! Can It get To cold while drying ? It's gonna be in low 60s and not humid..also gonna use a fan to blow in closet a little bit? What causes mold durring drying? Thanks a bunch for any help.. Bless up