GG4s gone purple

Hi guys.
Im new here and reaching out for any information on this problem. I'm a novice organic outdoor grower and had great success In the summer with a GG4 and Super Lemon Haze in a live soil. However on 2 clones I grew which were very large and beautifully green ( topped and loads of buds ) the leaves suddenly started to go purple and very dark. Is this down to cold temps or low pk. Have had them under a 600w hps for a few weeks and buds are showing signs of puffing up but very slowly. Any advice would be greatly appreciated.

Genetics.. Looks like a purple pheno..

I second that.. looks healthy, the purple is genetics in your case not deficiency

Thanks Dan, They're Gorilla Glue 4.

Genes man … genes.