You are out of the growth stage. The lowest leafs are just a causality of energy/food war going on with your plant.
As for the yellowing. You need a PK boost. Idk if the growth will have enough PK in it but it won't hurt, get niobium bloom or some PK booster . Really you need bloom but if you only have grow then yes, give her some feeds it might help a little but you need pk.
Good luck.