I'd also switch to tap water fro the Calcium in it. The leaves that are already dead look to me like they had been Ca deficient, among other things.
You are ready to start feeding.
I see what looks like a potassium deficiency too, but it could be scarring from previous insect damage. Looks more like K def though. The brown spots. Plus N def- the splotchy paleness around them.
A feeding with fish emulsion should take care of both the N def and the Ca problem btw.