Working a single crochet edging along a piece of knitting is quite easy — if you already know how to crochet. If not, it could take some practice. Should you decide you don’t like to crochet, an easy knitted substitute is as follows: With RS facing, pick up sts along the entire edge of the knitted piece. If desired, purl 1 WS row. Bind off loosely.
To work a single crochet edge:
1) Insert the crochet hook in the first stitch on the far right edge of the knitted piece. Pull up a loop of yarn. 1 loop is on the hook.
Note: Wrapping the yarn around the hook is called “yarn over” in many crochet patterns. This is a different motion than a yarn over in knitting. Make sure the hook is pointing down toward the bottom of the work to make it easier to pull it through the stitch.
3) Insert the hook into the next stitch to the left (see figure below). Pull up a loop of yarn. 2 loops are now on the hook.
4) Wrap the yarn around the crochet hook (see figure below). Pull the yarn through both loops that are on the hook. 1 loop remains on the hook and 1 single crochet stitch has been completed.
Repeat steps 3 and 4 along the entire edge of the knitting. If you want to work around a corner, you can keep going. Just work 3 single crochet stitches in the corner stitch. Fasten off the last stitch and weave in the ends.
Just as when you are picking up stitches, you have to get the right number of sts crocheted for the edge to be flat and smooth. If the edge pulls in, you need to work more crochet stitches, closer together. If the edge ruffles and flares out, you need to work fewer crochet stitches, skipping some knit stitches if necessary. In addition, everyone has a different crochet gauge, so you may need to try going up or down a hook size to get the desired results.