Thyme and basil are growing nicely. I've got all of the seedlings transplanted into Perlite. Apparently Perlite is some kind of volcanic rock that's heated up, then expands, making a really lightweight little pebble like thing. It's got lots of surface area and lots of empty space, so roots can move easily through it, and water drains well. And its sterile, so fungus shouldn't be a problem. (Though there are some little fuzzy things growing on a few of my peat pots.
The seedlings, overall, seem pretty healthy. But since I've transplanted them all, I'm bored. So I'll try fertilizing them. Perlite has a little bit of plant food in it. Maybe more is better. I got some Miracle-Gro Liquid Quick Start plant food and mixed a little up at half strength and gave them all a little feeding.