As the title says, the first set of true leaves turning yellow. What could be the possible cause? I'm sure this is not overwatering, as I'm keeping it on the dry side, so it's possible that's not enough water? Or something to do with nutrients?
6 weeks is when usually startsoils are depleted so that could be just about time. Its ot a problem since she will have made a lot of roots in search of water and food. For six weeks she is a little on the short side for an autoflower. Your temps not too low at night?