2. Just be sure you buy potting mix, not garden soil. MiracleGro and Pro-Mix seem to be the most popular with wintersowers. Some folks have had bad experiences with really cheap brands, saying that they turn into bricks later.
3. No fertilizer is necessary to start. It will probably just wash out before it's needed. The seeds have all they need to grow until they get to one leaf stage, then you begin to feed with a very dilute fertilizer.
I'll probably go with the MiracleGro potting soil (from my local HD). Usually, they sell it with fertilizer mix in that feeds for up to 4 months ... is this ok to use or should I look for soil without fertilizer? Also, what is sterile soil?
I use the Miracle Grow with fertilizer also. Michaeljo, before you plant your seed, make sure you read the pkg direction on the depth you need to plant. Also I use spagum in a thin layer over some of the very small seeds that need to be just barely covered. For super small seeds, I use an old salt shaker filled with play sand, add the seed and liberally shake away. I get a much more even distribution of seed and better germination that way.