Plant deficiency pale/yellow leaves

Hey, it looks like she could use some nitrogen. It's also important that you add CalMag. I think you can start with an NPK fertilizer. I use one in this phase with values of 10-4-7 or 7-3-5; you can find both at the hardware store and they're relatively inexpensive. They're usually stronger than what you get at the grow shop.

I see perlite so I guess it isn't overwatering but never rule that out, soil can do weird things locally (like pockets of waterlogged soil, pockets of lockout, etc.).. Generally speaking, the fact it is on the bottom is key. Observe there is no particular preference for intervein, edge, or vein yellowing. Those combined do indeed seem to indicate an N def