A step by step tutorial on how to do the mattress stitch for garter stitch and joining two pieces together without a visible seam.
You just finished a project and now it’s time to join two pieces together (or one flat piece in the round? But you don’t have a clue how to seam garter stitch? Well, you came to the right place because this step-by-step tutorial is all about it. I tried to include big pictures and even a video so you can get it right on your try – even if you are a beginner.
Mattress stitch is a great way for vertical seaming. Sadly, the classic technique only works for stockinette stitch. But if you add a little twist, you can easily make it work for any pattern knitted in garter stitch as well and use it to join your mitered squares together.
Tip: If you want to close horizontal seams, check out my tutorial on grafting garter stitch.
This version results in a flat seam that barely has a jog and I found it to be the best and most invisible way to join garter stitch. There are certainly other ways, but a lot of them result in a little welt on the wrong side.
While this method won’t be 100% invisible on the wrong side either, it doesn’t create a ridge or anything too noticeable. For all practical reasons, it lays perfectly flat. This also means it’s a great way to create tubular objects (socks, hats, etc) in case you don’t want to knit garter stitch in the round.
So, let’s dive right into the seaming, eh?
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- Thread a little length of yarn on a blunt tapestry needle (or use the cast-on/bind-off tail if it's long enough, and align the two pieces so they are both facing you with the right side. So, the cast-on tail should be on the bottom right on both sides.
- Pull the yarn through the last stitch on the left side and then through the last stitch on the right side.
- Next, push your tapestry needle through the bottom bump directly on the edge of the piece on the left side. It looks a little bit distorted and is sort of squeezed in below a much better visible top bump.
- Go through the top bump at the end of the first ridge on the right side.
- Then, pull the yarn through the bottom bump on the right side which is one ridge above.
Click on the link, if you don't know how to count rows in garter stitch.
- Pull your tapestry needle through the top bump on the right side, also one ridge above.
- Repeat steps 5+6 until you finished the seam.
Give the tail a gentle tug every inch or so to close the seam. Don't pull too tightly, though. This might pucker/cinch the fabric too much.
If you want to seam together larger projects, consider pinning them together lightly, so they don't move too much as you sew. You can also use your fingers to pin a smaller project together.
Also, make sure that you always go in from left to right on the left side and from right to left on the right side. Otherwise, your seam will not look all that neat.
To close the gap at the very top of the seam, graft a knit stitch to create an invisible bridge joining the two bind-off edges together.
Here’s another close-up shot in case you have trouble identifying the two different bumps. It can be sometimes a bit hard, especially there at the edges. It often helps to look at the previous stitch. If that’s a top bump, then the next little distorted stitch has to be a bottom (and vice versa).