Granddaddy Purple by Best Coast

We are in Week 7 Day 2 of this grow.Buds have been swelling up for the last three weeks. They are finally starting to show signs of purpling but I may have to run these for another week to make sure they purple out. Never grown GDP so I don't know if cold manipulation is needed for a strain that is supposed to be a purple strain. I have the temp dropping down more than 10 degrees (64F) at night so that should encourage the plant to start using up the energy stored in the leaves.