Ribbing is a special pattern of stitches that causes the fabric to contract widthwise, but still retain its ability to stretch to its full width, and so it is often used for cuffs on sweaters and socks. In knitting, ribbing is achieved by alternating knit and purl stitches, but in crocheting it is achieved by alternating back-post stitches with front-post stitches.
If you've never done post stitches before, please see our tutorials on back-post stitches and front-post stitches. And for the most stretch in the ribbing, we recommend using a crochet hook that's a size or two larger than the crochet hook used for the rest of the project.
And without further ado, here's how to do crochet ribbing.
Row 1. Dc in 3rd ch from hook and ea rem ch across.
Row 2. Ch 2 (counts as 1 dc now and throughout); turn. *Fpdc around next dc, bpdc around next dc; rep from * across.
Row 3. Ch 2; turn. *Bpdc around next fpdc, fpdc around next bpdc; rep from * across.
Row 4. Ch 2; turn. *Fpdc around next bpdc, bpdc around next fpdc; rep from * across.
Rep rows 3 & 4.
bpdc back-post double crochet
dc double crochet
fpdc front-post double crochet