When to start fertilizing when using peat pellets?

[BennB]

I know this topic has likely come up many many times, but every time I search for it I keep coming across other interesting threads and keep getting sidetracked!

In the past I started seeds in a basic seed starter soil mix. This year my kids bought me a seed starter kit with the peat pellets. We planted them about a week and a half ago and they have germinated and just I put them under lights today. They still just have cotyledon leaves and are about 2" tall.

My question is: when do I need to start fertilizing them? I usually have not fertilized starts until I transplant them into 4" pots, Which is usually 4 or so weeks into the process after they get at least two bunches of true leaves. Since the peat does not have the same nutrient mix as starter soil, is this OK?

Also, I usually use standard Miracle Grow when I pot up starts, mixed about 1/2 strength? Is that too strong a concentration for such small seedlings?

Thanks!

Benn