So my girl is about 4 -5 weeks old. She's in a coco/fox farm soil mix. She gets 6.4-6.5 ph'd water when needed. I have been having this problem for a few weeks now. I didn't feed her for about a week , no change. About 6 days ago I fed her a half dose of fox farm big grow and big bloom. I've watered once sence then. The lowest sun leaves start to yellow and as they get worse the next set of sun leaves above starts the cycle! It might not be anything to worry about, but if I'm doing something wrong I want to fix it!!