Soil for indoor seed-starting

I should mention, I'm trying a different approach with indoor seed-starting medium this year.  In past years I always used vermiculite, with several seeds all in one margarine tub, as in Mel Bartholomew's Square Foot Gardening book, which was the first how-to gardening book I read.  That was back in the 90s when I had a plot at the Three Sisters Community Garden on University of Ottawa property -- which, sadly, later turned into a shiny new building.

This year, since I was almost out of vermiculite, I figured I'd try something else.  So, this year everything is being started in soil, and, right in their hopefully-one-and-only-indoor-pot, so less transplanting needed.  Each pot will have at least one backup seed in the hopes that at least one will germinate.