Any type of good quality potting soil is fine. If you like MG, go with that, though I think I'd stick with the MG starting mix as I believe it's also recommended for use with transplants and young seedlings. The fertilizer in regular MG potting mix might be a big strong for your young seedlings.

I agree with sleepy. Stay with something that won't be too strong on your seedlings, at least until they are in early adult stages.

I use MG potting soil for my seedlings and they do great. I do not fertilize them until they get in the ground or container in the Spring because MG comes with fertilizer in it already, as you know.

I have not compared it with using a Pro-Mix or other brand so I cannot say it is better or worse, but it works for me.

Keriann~