does vanilla frosting typically not purple up, there is almost none on the entire plant, i was understanding the vegetative growth would gradually turn purple as phosphorous uptake increased?
It will change colours in the cold weather once its ready to harvest.
The phoenotype will dictate if it will purple up.
example. fastbuds blackberry is aorund 50/50 purple vs green.
however the Dinafem Dinamed CBD Kush auto has always been purple for me.
All boils down to how well the seeds are locked into their desired traits from the breeding practise. Given most places do not breed the plants are just while label resellers there is little control.
Good Luck!
What mOuse said. It all comes down to genetics and hopefully that best pheno of the bunch were bred. Alot of terrible genetics out there so always buy from good breeders.