Hi
@ccthefarmer not all plants gain these colors, depending on the phenotype and genetics of the plants some gain darker and purple tones and other plants do not. Female plants only change colors around 6-7 weeks of flowering, a factor that helps this color change is an environment with lower temperatures around 18 ° c. But there is nothing to do, your plants look healthy and happy, certainly in the last weeks of flowering the buds will gain beautiful tones and colors. good luck mate 👍