Why do the edges curl? This is a question that is asked by almost every single new knitter. The next question that follows is always how do I do to keep it from curling? or what can I do after it’s finished?
It really is a simple answer and a simple solution. And a rather short subject. But there are times that having the edges curl is a good thing although most people do not want their flat panels like blankets and scarves curling.
Why do knits curls?
When you use all knit stitches to create a flat panel, 
the bottom will curl up while the top curls down
and the sides will curl under. 
This is from the back so you can see it curl under.
It’s the nature of the knit stitch.
The horizontal knits or rows will pull the top and bottom of the stitch together toward the front of the stitch causing it curl up from the bottom and down from the top.
The vertical knits or columns will pull each side of the stitch together toward the back of the stitch causing the work to curl under on the sides.
What if I use all purls?
Then the work will curl in the opposite direction. Purl is just a backward knit. Turn the knit over and watch the magic happen. I mean the curling…
Then what do I do to keep it from curling?
If you take the info I just shared about how knits and purls curl in opposite directions, you will have your answer. You will need a combination of both stitches together to counter act each other to keep the work flat.
What stitches can I use?
Garter, seed, and moss stitch patterns are common borders for flat panels while rib and garter stitch patterns are common brims for hats or cuffs. I would not recommend using ribbing on a blanket since it draws inward. Works great for hat brims and cuffs on sleeves and mittens. But there are a variety of knit/purl combination stitch patterns that will work for borders.
You do not need to do the entire work in any of these stitches. You can just work a border for a flat panel or a brim for a hat.
For a border, you will need one on all 4 sides. Not just at the top and bottom because those sides do curl as well.
How do I work a border for a blanket or flat panel?
Using the stitch pattern of choice, start with a border of 3″ – 5″ for a blanket depending how how long you like it or how long your tolerance for purl stitches last. Smaller projects do not necessarily need wide borders.
If you haven’t worked a swatch to know how many stitches across equals the length of the bottom border, then measure how many stitches is in an inch and mark the pegs at that count on each side for the side borders. I love stitch markers. They help remind you when to start and stop that border.
Work each side in the same stitch pattern as the bottom and work the middle in all knit which is called stockinette.
Then when you get the blanket finished within the length of the bottom border, make the top border the same as the bottom border.
Why does my border curl up still?
Sometimes you will still get a curl if the border or brim is too narrow like this hat is doing.
This hat is still on the loom. There is only 4 rounds of ribbing for the brim so it turns up. The ribbing isn’t curling but has turned up where I started my all knit rounds. But once I get it finished and blocked, it won’t turn up. There may be a few other questions about this picture. Shhhh… You will find out soon enough.
The wider the border, the less likely it will curl since you have gravity in your favor. The weight of the yarn is what keeps the middle flat on a flat panel and only the ends and sides curl. Just make sure your border or brim is wide enough.
Can I just use a different cast on?
It doesn’t matter which cast on you use. It’s the knit stitch itself that curls. The cast on will not counter that.
What other ways can I use to flatten a flat panel that is already made?
If your project is already finished, you can block it. You can learn more about blocking here. I will say that if it’s 100% acrylic, you may not even want to attempt blocking. Blocking acrylic is tricky.
There are also loom knit borders you can add to a finished project by just picking up the edge stitches as you work the border.
Or if you know how to crochet, you can crochet a border on just like you add a border on a crochet project.
Why would I want my knits to curl?
Personally, I love a rolled brim hat for babies and kids. If you just knit all those first rows, then the bottom of the hat will roll up making a cute rolled brim.
Having a border of all knits that curl will make the edges softer on certain projects especially when the stitch pattern for the middle doesn’t curl.
I also love a rolled cuff on a super bulky over-sized sweater.
Well I hope this helps with the curling problem. No perms or straighteners needed. Only a combo of knits and purls. And please don’t hate the purl stitch. It gets very sad when ignored.
Happy loom knitting!!