MUDBUGanswered grow question 6 years ago You are futher than 3 weeks your at at least 40 to 50 days your lower leaves will start to turn yellow and No its not a defiency your as your plant ages your leaves will start dying at the bottom of your plant just prune them off you are in the second week of flower your plant knows its life is comen to the end you did good on her i would bump up watering t she looks a lil underwatered but u picked a strain that is not the easiest to grow looks good✌️✌️👍👍👏👏Good luck with her and do a 21 day flush if u want to see her really SHINE👁️👍👍