How to Seam Knits with Square Chain Stitch

It all started with a sweater (if you are curious, you can see it in this video). I knit it in fisherman’s rib, and when it was time to seam the sides and the sleeves, I wanted the seam to be invisible, flat, stretchy and preferably reversible (in case I decide to wear the sweater inside out). 

No seam I knew fitted the bill. So I started experimenting with different options and found a seam that is almost perfect. Well, nothing is perfect, but this seam is coming close to that.

It is based on a lovely embroidery stitch called “square chain”. It is explained in this extremely helpful reference book. 

Embroidery is a slow and elaborate craft, and this embroidery-based seam is not a quick way to stitch knitted pieces together. It will take time, but the final look is absolutely worth every minute you’ll spend.

A FEW TIPS BEFORE WE GET STARTED

1. Square chain seam looks best on edges that have a slip stitch selvedge or no selvedge at all. 

If you want the seam to be invisible, use the same yarn you used for the project (as I did when I was seaming these two swatches):

Of course, you can choose a different colour of yarn to use the seams for decorating your project. 

For the video tutorial and step by step photos in this article, I used a different coloured yarn to make it easier to see how this seam is made. Hopefully, it’ll help you master it without much confusion.

2. Because this seam mimics the look of knit stitches, it works best on stockinette stitch and ribbing patterns. It will look nice on other patterns too, but it won’t be invisible. 

Ok, now let’s see how the square chain seam works.

GETTING STARTED

Start seaming at the cast on edge. This way the chains we create with the seam will be very similar to the knit stitches of the fabric.

If you plan for this seam beforehand, and the seam is not going to be too long (for example, if you knit a cowl, a hat or a baby jacket), leave a loooooong tail when you cast on stitches. I used a funny word “loooooong” to emphasise that the tail should be very long. 

This seam uses a lot of yarn, so make sure the tail is about five times longer than the length of the future seam. For example, if a cowl is 40cm / 16″ long, the tail should be at least 2 meters / 6.5 feet AFTER you cast on the stitches. 

You can easily avoid this planning part if you are not afraid of weaving in two extra tails. Because I use a different colour of yarn for my seam, I simply cut a piece of yarn that is about five times longer than the length of the swatches I plan to stitch together.

Thread the yarn (or yarn tail) into a wool needle and align both pieces of fabric side by side with the knit side of the work facing to you.

1. First, we need to secure the very beginning of the seam. Insert the wool needle from back to front into a spot that is one stitch away from the edge at the very bottom of the piece on the right.

Pull the yarn through. If you use the yarn tail that you left when you cast on stitches, pull it all the way through. If you use a separate piece of yarn, leave a small tail at the bottom of the seam to weave in later on.

2. Now insert the wool needle from front to back into a spot that is one stitch from the edge at the bottom of the piece on the left, and from back to front into the same spot we used in step 1.

Pull the yarn through and tighten it.

3. Repeat the previous step, but this time don’t pull the yarn tight right away. Leave a small loop, then insert the wool needle into that loop in the direction towards the cast on edge. Pull the yarn to tighten the loop some more.

SEAMING

From now on we’ll be using the stitches that are at the very edge of each knitted piece. But we won’t use both legs of each stitch – just the leg that is further from the edge. Here’s what I mean. Let’s call it the “working leg”.

1. Insert the wool needle into the same loop from which the yarn comes out.

2. Then into the working leg of the next stitch of the piece on the left.

3. And finally into the working leg of the next stitch of the piece on the right.

4. Pull the yarn through leaving a small loop.

5. Insert the wool needle into that loop in the direction towards the cast on edge. Make sure the loop is not twisted.

6. Pull the yarn to tighten the loop, but don’t make it too tight. It should be as big as the knit stitches of the fabric.

Repeat the six steps of the “seaming” section until your knitted pieces get joined with a lovely seam!

FINISHING

This part is the easiest one. Once you join all stitches of the seam, move the yarn over the last loop and to the back of the work. Secure it at the back and cut the yarn.

---

If you enjoyed this tutorial,
here’s something else you might find helpful:

---

---