The three main methods for joining shoulder seams

Shoulder seams in knitting are joined using one of three techniques: the three-needle bind-off, the Kitchener stitch (also called grafting), or a backstitch seam. The three-needle bind-off is the fastest and creates a visible ridge on the inside of the garment. The Kitchener stitch is invisible from both sides and works best when you have live stitches on both pieces. The backstitch seam is the most traditional and works with bound-off edges, though it leaves a visible line on the inside.

Your choice depends on what you have at the end of each shoulder piece. If you stopped knitting and bound off both sides, you will use backstitch. If you left stitches live (unbound) on both shoulders, you can use either the three-needle bind-off or Kitchener stitch. Most modern patterns ask you to leave stitches live specifically so you can use one of the first two methods, which are stronger and less likely to split.

Key Takeaways

  • The three-needle bind-off is the fastest method and works when both shoulders have live stitches; it creates a ridge on the inside of the garment.
  • The Kitchener stitch produces an invisible seam and works best for shoulders where you want no visible line, but it requires more practice to execute smoothly.
  • Backstitch seaming works with bound-off edges and is the method to use if your pattern did not leave stitches live on the shoulders.
  • Block your pieces before joining if your pattern calls for it, because seaming is much easier on flat, even edges.
  • Weave in all ends before you seam, not after, so you do not have to work around them while you join.

Three-needle bind-off for live stitches

The three-needle bind-off joins two pieces of knitting by binding off through both layers at once. Hold the two shoulder pieces with their right sides facing each other and the live stitches lined up on two needles of the same size. Insert a third needle (one size larger is optional but makes the seam less tight) through the first stitch on the front needle, then through the first stitch on the back needle, and knit them together as one stitch.

Repeat this for the next stitch on each needle so you have two stitches on your working needle. Pass the first stitch over the second stitch to bind off, exactly as you would at the end of a row. Continue across until all stitches are bound off. The seam will be visible as a ridge on the inside of the garment, but it is very strong and will not unravel.

If your shoulder stitches do not line up exactly — one side has more stitches than the other — you can decrease on the side with extra stitches before you begin, or you can knit two stitches together as one when you encounter the mismatch. The seam will still hold.

Kitchener stitch for an invisible seam

The Kitchener stitch (grafting) joins two pieces so the seam is completely invisible. Like the three-needle bind-off, it requires live stitches on both shoulders. Thread a tapestry needle with the same yarn you used for the garment. Hold the two pieces with right sides facing you and the live stitches on two needles held parallel, one in front and one in back.

The pattern is: insert the tapestry needle through the first stitch on the front needle from right to left (as if to purl), then through the first stitch on the back needle from left to right (as if to knit). Go back through the first front stitch from left to right (as if to knit) and drop it off the needle. Go through the next front stitch from right to left and leave it on the needle. Repeat the same steps on the back needle. The rhythm is purl-knit on front, knit-purl on back, and you drop one stitch each time you complete both sides.

This method takes longer than the three-needle bind-off and requires steady tension so the grafted stitches match the rest of the fabric. If you pull too tight, the seam will pucker. If you pull too loose, it will gap. Practice on a swatch before you graft your shoulders.

Backstitch seaming for bound-off edges

If both shoulders are bound off, use backstitch to join them. Thread a tapestry needle with yarn and lay the two pieces flat with right sides facing up and edges aligned. Insert the needle through the first stitch on one piece, one row in from the edge, then through the corresponding stitch on the other piece. Bring the needle back out one stitch forward on both pieces and insert it back through the stitch you just came out of, creating a backwards line.

Work along the seam one stitch at a time, staying one row in from the edge so the seam sits inside the garment. The backstitch seam is visible from the inside but creates a clean line on the outside. It is also the most forgiving method if your edges are slightly uneven, because you can adjust your tension stitch by stitch.

For a neater backstitch, use yarn that matches your garment exactly and split the yarn if your working yarn is thicker than the stitches you are sewing through. A seam that is too thick will create a bulge at the shoulder.

Preparing your pieces before you seam

Before you join the shoulders, block your pieces if your pattern calls for it. Blocking makes edges even and gives you a clear line to follow while seaming. Wet-block by soaking the pieces in cool water, squeezing out excess water gently, and pinning them to shape on a blocking board. Let them dry completely — usually overnight — before you remove the pins and seam.

Weave in all yarn ends before you seam, not after. Once the seam is complete, you cannot easily access the inside of the shoulder to hide ends. Use a tapestry needle to thread each end through several stitches inside the garment, then trim it close to the fabric.

If your pattern has you pick up stitches for a neckband after the shoulders are joined, seam first and then pick up. The seam will anchor the neckband and prevent it from pulling away from the shoulder line.

Fixing a seam that does not lie flat

If your shoulder seam puckers or gaps after you finish, the most common cause is uneven tension. Backstitch seams that are too tight will pull the shoulder inward. Kitchener stitch that is too loose will show gaps between stitches. Three-needle bind-off seams rarely have this problem because the bind-off itself controls the tension.

For a backstitch seam that is too tight, you can carefully rip it out and resew with looser tension. For a Kitchener stitch that gaps, you can tighten individual stitches by pulling gently on the working yarn and working backwards through the grafted section. If the problem is severe, ripping and regrafting is faster than trying to fix it stitch by stitch.

If the seam lies flat but the shoulder itself is bunched or twisted, the problem is usually that the two pieces were not aligned correctly before you started. This is harder to fix without ripping the seam and starting over, so take time to line up your stitches carefully before you begin.

Frequently Asked Questions

Can I use the three-needle bind-off if one shoulder has more stitches than the other?

Yes. Before you begin, decrease on the side with extra stitches until both sides match, or knit two stitches together as one when you reach the mismatch during the bind-off. The seam will still be strong.

What yarn should I use to seam the shoulders?

Use the same yarn you knitted the garment with, in the same color. If the yarn is very thick, you can split it into thinner plies so the seam is not bulky. For a backstitch seam, match the color exactly because the seam is visible from the inside.

Do I have to block my pieces before I seam?

Blocking is not required, but it makes seaming much easier because the edges are even and you have a clear line to follow. If your pattern does not call for blocking, you can seam without it, though the result may be less neat.

Which method is strongest for shoulders?

The three-needle bind-off and Kitchener stitch are both very strong because they join live stitches. Backstitch seaming is also strong if you use consistent tension and do not pull too tight. All three will hold up to normal wear.

What if I accidentally bound off both shoulders and now I cannot use the three-needle bind-off?

Use backstitch seaming instead. It works just as well with bound-off edges. You can also pick up the bound-off stitches with a needle and use the three-needle bind-off, but this is more work than straightforward seaming the edges as they are.