Hey Larry this one is for you. Many others I'm sure are wondering the same thing as well. The question here is whether or not to use fertilizer on seedlings and when and also what is the best kind of soil to use for re-potting from peat pellets.
I also start my seeds in peat but many say potting soil is better. In my experience, I disagree. If you are going to re-pot then peat is a good starting medium. When you go to re-pot into larger containers, I would switch to a well balanced nutrient rich potting soil for vegetables. This will ensure you have the correct amount of nutrients for your seedlings to grow.
As far as using fertilizer, I have never used it on seedlings. My advice is to not use any until your plants are hardened off and planted in the garden. Young seedlings are very delicate and the fertilizer can potentially burn them in a way and end up hurting them. There are many kinds of potting soils out there with low doses of fertilizer mixed in which will provide enough during that critical growing time. At the same time though fertilizer is meant to promote either blossoms or better fruit. Applying fertilizer to a seedling could make the plant become spindly and lanky. This is something we do not want our seedlings to do.
My advice is to wait on the fertilizer until your can move things outside. This will ensure your plants are ready for the doses you are about to apply.
Hope this helps, let me know if you need any clearification.
