The garter, stockinette, ribbing, seed, and double seed are the basic stitches of knitting. They are different combinations of the two manners to slip the yarn off the needle. If the yarn is taken off the back, it is a knit stitch; off the front is a purl stitch.
The garter stitch is when you knit every row; this is the simplest stitch to do because it only uses one stitch. The stockinette is when you alternate between knitting a row and then purling the next; this is the stitch used most in knitting because it has a smoother appearance when compared to the garter stitch.
Ribbing is the stitch of the finished edges to keep the knitting from rolling up which is what will happen if just the stockinette stitch is used. Ribbing is knitting one stitch and then purling the next. The odd rows begin with a knit stitch and the even with a purl stitch, so it is done on an odd number of stitches to obtain the ribbing effect. A variation of simple ribbing is the double ribbing stitch where there are two knits and then two purls; this stitch is done on a multiple of four stitches plus two.
The seed and double seed stitches are similar to simple ribbing in that you knit one stitch and then purl one, beginning with a knit stitch on the odd rows and a purl on the even rows; however, the seed stitch is done on an even number of stitches instead of an odd number. The double seed stitch is two rows that begin with a knit stitch and then two that start with a purl stitch. These four rows are repeated.
These stitches do not require the crossing over of stitches, the knitting stitches together or the adding of stitches. These techniques are used to acquire a braided look or lace-like look.