One of the most common questions from beginning knitters has to do with curling Stockinette Stitch. They wonder if they're doing it wrong because, when knitting plain Stockinette Stitch, the edges curl up, often quire dramatically.
What Curled Stockinette Stitch Looks Like
If you knit a flat swatch of Stockinette Stitch, bind off and let it go, you'll see that it either rolls in at the edges or rolls into a tube.
When you work Stockinette Stitch in the round, you'll see the cast on and bind off edges curl. Sometimes this is used as a design feature in projects, such as this roll brim hat and these rolled cuff toddler socks.
But often this is a look we do not want, such as when knitting a scarf or a square for an afghan.
Why Does Stockinette Stitch Curl?
The reason it curls has to do with the very structure of the stitches.
When you're working a pattern that has knits and purls on both sides, this difference in stitch size doesn't matter, but when you're working in stockinette stitch, where all the knit stitches are on one side of the work, the knitting tends to curl.
How to Avoid Stockinette Stitch Curling
If you haven't yet knit a project that you want to be Stockinette Stitch but you don't want it to curl, the most common option to minimize or eliminate curl is the use of border stitches knit in a different stitch pattern as you knit the rest of the project.
Many Stockinette-heavy knitting patterns have an edging of ribbing, Moss Stitch, Seed Stitch or a similar pattern that includes knits and purls in a relatively even measure, which helps balance out the rows to limit curling.
You'll probably need five or six stitches at each side and five or six rows at the beginning and the end to prevent curling.
On hats and socks, I usually knit at least an inch/2.5 cm in ribbing or another non-curling pattern before moving on to Stockinette.
Another option is to knit Stockinette in the round. The cast on and bound of edges will still curl, but you can, for instance, knit a scarf in the round, then add tassels to the ends that will hold the edges flat.
How to Fix Curl in a Finished Project
What if you've already knit a project and don't like the curling? There are a few options, some of which work better than others.
Some people will tell you that blocking will help smooth out Stockinette, and sometimes it does, at least temporarily, but it's not a sure-fire fix, and it won't last.
A form of blocking known as killing can be done on acrylic yarns. It involves using an iron to melt the fibers into position permanently. But, as you might imagine, this alters the look and texture of the yarn dramatically, so test a swatch to be sure you'll be happy with the results before you do it on a whole project.
You can add a crocheted border around the edges of the knit item, but much like knitting on a border, it will have to be pretty large to make a difference, and you might lot like the result (if, say, you knit a scarf the width you want and don't want to have to add a couple of inches on all sides).
Other options from the always awesome Tech Knitting site include intentionally dropping stitches, which opens up the fabric and gives it a lacy look; dropping stitches and changing the scarf to ribbing instead of Stockinette; and lining the scarf with fabric, which holds it in place.
Finally, you can also just call it a design element and live with the curl.