Indoor LED Auto Pineapple Express

Was cruising along. Buds are fattening up a bit and I can really get a whiff right before the lights come on and after a watering. Then noticed purpling on stems and some lower yellowing fans. Worried but not too much... The breeder has this strain at 4wks veg and 30 days flower unless I understood that wrong. My girl needs more than 30 days by the looks of the buds and trichomes. The purpling...I haven't seen anything about this strain purpling. Uh oh. All three strains in my closet (all different and two are clones) have started purpling a bit just stems. Could it have anything to do with the new better lights, like some stress reaction? Or a nute or ph issue? I dont know. Maybe a flush...