Ribbing that holds its shape

Ribbing is the stretchy fabric at the cuff, hem and brim of most knitted garments. It works because alternating knit and purl columns draw the fabric together, so a rib that measures 10 cm resting can open to 15 cm or more when stretched. Choose the wrong rib, needle or number of rows and it flares, rolls or goes slack, but the fixes are simple.

1x1 and 2x2

1x1 rib alternates one knit, one purl. It is the most elastic and pulls in the tightest. Because the columns are narrow, it is slow to work and best for fine yarn, small pieces and the cuffs of socks.

2x2 rib alternates two knit and two purl. It is thicker, more relaxed and faster to work, with columns that stand out. It is the usual rib for hat brims, sweater hems and scarf edges in worsted and bulky yarn.

Other ribs, such as 3x1 and 1x1 twisted rib, appear in pattern stitches. Both 1x1 and 2x2 have entries in the stitch database with the multiples of stitches they need: 1x1 works over any even number, 2x2 over a multiple of four, and a multiple of four plus two makes the ends match when worked flat.

Why ribbing pulls in

The knit columns are pushed forward and the purl columns backward, and the fabric folds along those lines. The folds draw the width in by up to a third compared with stockinette worked over the same stitches. That is why a pattern cuts the needle size or the stitch count for the body when it moves from rib to stockinette: a hat often has the same number of stitches in both, but the rib is knit on a smaller needle, so that it sits close to the head.

Needle size

Use a needle one or two sizes smaller than for the body. The firmer rib keeps its shape and does not flare. If the needle is the same, the rib is often loose and spreads; if it is three sizes smaller, the rib can stretch only with force and puckers the edge when it is bound off. Check sizes in the needle database, which lists metric and US together, so you can step down in single sizes.

Why a cuff flares at the top

• The rib is too short. Less than 3 cm of rib does not have time to pull in. A hat brim of 4 to 6 cm works; a sock cuff of 3 to 5 cm; a sweater hem of 5 to 8 cm.
• The stitches changed after the rib. When a pattern changes from 2x2 to stockinette, the body may need extra stitches to make up the width; if you do not increase, the rib pulls in, but if you do increase too much the edge flares. Follow the count in the pattern.
• The bind off is too loose. A tight rib needs a stretchy bind off. A very loose bind off frills out. Bind off in pattern, knitting the knits and purling the purls.

Why a cuff goes slack

• Wool with good memory keeps ribbing tight. Cotton, linen and bamboo have little stretch recovery and ribbing in those fibres can relax and sag after a few uses or a wash. Choose a blend with a touch of wool or an elastic core for cuffs in plant fibres.
• Knit stitches have a little more give when they are loose. A rib with very loose tension droops. Keep the tension even, especially on the purl stitches, where it tends to relax.
• Twisted rib, where the knit stitches are worked through the back loop, is firmer and keeps its shape. The twist also makes the columns sharper.

Keeping the pattern straight

Ribs look messy when a knit stitch slips into a purl column. When you change from knit to purl, bring the yarn to the front between the needles, and take it to the back again to knit. Move the yarn between the needles rather than over them, so it does not make an extra loop. After the first few rows, read the stitches: knit stitches look like Vs, purl stitches like bumps, and the pattern should stay in straight lines.

Matching the rib to the piece

Hats

For a beanie, the cast-on count must be a multiple of the rib. A head circumference and gauge give a target number, and the hat designer in the tools section chooses a count that fits the rib and the crown decreases, so you do not have to adjust it by hand.