You don't need anything special for seed germination. Most of the typical packaged potting mixes are perfectly suited for that task, being rather fine textured. That quality makes them pretty awful as a potting mix but great for seed starting. Don't buy into the marketing ploy that dictates the need for something special.

Bottom heat is more important in the germination process than a special medium. Then, moisture management, light, air temperature, and other environmental factors become important.

I like a layer of finely milled sphagnum moss on top of whichever soil mix I have. It helps keep the seeds from drying out. I'm usually sowing very fine seed for which this works especially well. But I've been planting garden seeds lately using the same method. They have been coming up very quickly, too.

Me too. I use a very well-aerated soil with the seeds scattered on top. Then I cover the seeds with a light covering of fine peat, Turface fines, or a mixture of both, and keep the top moist via misting and partially tenting until seeds germinate, at which time I eliminate bottom heat if I'm using it. Seedlings appreciate a well-aerated medium as much as a mature plant. If the seeds are very fine, I usually mix them with some Turface fines (sand works well) and sprinkle the mixture over the coarse medium before covering.

Al