Also, what is the difference between the seed and moss stitch?
You must have an odd number of stitches for this to work in the round. Just (knit 1, purl 1) repeat until finished.
There is no difference between seed stitch and moss stitch. They are just different names for the same stitch.
To knit seed stitch in the round you knit 1, purl 1 to the end of the round. On the next round purl the knit stitch and knit the purl stitch. In other words a knit stitch must fall on top of a purl stitch and a purl stitch sits on top of a knit stitch. I am not sure how many stitches you need to cast on in order for the work to come out so that you can alternate stitches. I think it should be on odd number of stitches. But try it out on a swatch first.
Seed stitch and Moss stitch are different names for the same stitch.
look at this link: http://www.knitting-and.com/knitting/patterns/stitches/moss.htm
the first example, I have always seen referred to as seed stitch, while the second has always been moss, or Irish moss.