When I thought up the 12/12/12 scarf in the middle of the night my idea was to capture the date in yarn.
I wasn’t alert enough to consider that 12 sts in stockinette stitch on either side would curl right up.
This issue became rapidly apparent to me when I finally started knitting the scarf that evening.

Stockinette Stitch sides curl right up
Of course, I had to follow through with the pattern as I’d presented it so you could see how it would turn out.
Curling stockinette stitch is something with which all knitters struggle. Either you are a new knitter wondering why it happens or you are an experienced knitter trying to prevent it.
In her book “The Principles of Knitting”, June Hemmons Hiatt explains the curling happens because of the shape of the stitches. She points out that the stitches are pulled tight at the bottom by the row below and flair out at the top. This creates tension in the fabric and causes the curl.
Combat the Curl!
Now that we know why the curl happens, what can we do to manage it?
First you have to decide whether it’s really an issue for your project.
Part of me wonders whether it really matters that a scarf is curling since it’s just going to get folded and bunched up anyway. But I do want options for how I wear it and don’t want my hard work to be hidden.
If this was part of a sweater the curling wouldn’t matter since the pieces would be stabilized when they are sewn together. In the case of a sweater, the curl only matters when you are trying to flatten the pieces out for seaming.
When I posted a picture of the curled up scarf on our Facebook page many people jumped in with suggestions about how to fix it.
Block It
You’ll want to take into account the washing instructions for the yarn and the durability of the project when deciding on a method.
For this scarf using Juniper Moon Farm Chadwick yarn I could soak it in cold water, gently remove the excess water, and pin it in place.
I could also use a spray bottle to mist the scarf before pinning it in place instead of soaking it.
Steaming it with an iron might work as well.
The problem with blocking is that it wears off. Especially on a scarf, which gets bunched up when you wear it.
I would need something more permanent.
Work a Slip Stitch Edge
This is just how it sounds. You slip the first stitch of the row instead of working it.
You slip it opposite of how the stitch is presenting. So if you are looking at a knit stitch you would slip it purlwise. If you’re looking at a purl stitch slip it knitwise.
This also makes a nice, neat edge.
Honestly, I didn’t think that would work in this case because there was such a wide expanse of stockinette to contend with. I didn’t even try it. but you might want to give it a whirl for educational purposes so you better understand the method and how it behaves.
Work an Edging
This was the winning idea.
Of course, by working an edging I was getting away from the 12/12/12 theme, but I decided an un-curled scarf was more important than the theme!

Ribbing helps a bit.
The first edging I tried was a 4×4 ribbing.
In long hand that translates to:
p4, k4, p4, k12, p4, k4, p4
K4, p4, k4, p12, k4, p4, k4
Repeat for 12 rows total.
P4, k4, p4, C12B, p4, k4, p4
etc.
You can see that after several rows of that I got bored and started adding cables to the K4 column on either side of the central cable.
The small cable on the right is crossed to the back while the small cable on the left is crossed to the front.
I started crossing them at the same time I crossed the central cable to make it easy to remember. For a different look you can cross the small cables at a different time than the central cable. For instance, if you were starting the scarf from the beginning, you can cross the small cables for the first time on the 6th row and then again 12 rows later on the 18th row, but still cross the big, central cable every 12th row.
Or cross the small cables more or less frequently. But you get the idea that there are many options.
As you can see in the picture the outside edges are still curling in a bit. I think in this case a slip stitch edge would help since it’s only fighting against 4 sts.

Seed stitch flattens it out
The next edging I tried was seed stitch.
As you know the first row of seed stitch is a K1, P1 rib across. Then on the second row you purl the knits and knit the purls.
I maintained a two purl stitch buffer on either side of the central cable.
The seed stitch flattens the scarf right out. Like a pancake!
That’s because there aren’t smooth columns of stitches to pull against each other and cause the curl.
This is actually a pretty classic scarf pattern and you’ll find many examples of it at your local yarn store using different yarns.
The only problem with it is that all that switching back and forth between knits and purls can slow you down.

You can see it flattening out with the different side options.
Here is a picture of the full scarf. You can really see how the different sections are behaving. It’s interesting to see the scarf getting flatter as I progress through the different edging options.
Another edging that was suggested was garter stitch. You would knit the first and last 3 or 4 sts on each row every row.
You can combine the garter stitch edge with the rib and cable edging by working garter stitch over the first and last few stitches instead of purling them.
I suggest you use stitch markers to box off your garter stitch section so you don’t accidentally work too many stitches.
Something to keep in mind is that garter stitch has a different row gauge then stockinette stitch and might pull against the rest of the knitting if you make your garter stitch section to wide.
You’ll want to knit a generous swatch to test your options.
Personally I haven’t decided which edging to use, but I’m leaning toward the rib and cable option.