Seaming garter stitch for beginners

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.

two pieces knitted in garter stitch joined together using mattress stitch using a contrasting yarn

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. And here is a method to join edge stitch to cast-on stitch.

close up of the finished seam using the mattress stitch for garter stitch in the same color
Right side of the seam

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.

wrong side of the garter stitch seam where you can barely see a ridge
Wrong side of the seam

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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How to seam garter stitch

seaming garter stitch with the mattress stitch using a red contrasting yarn

Seaming garter stitch with the mattress stitch method boils down to going through different parts of the ridges on both sides. Each ridge consists of two parts: A bump that looks like a little bowl and one that appears to be a little dome. They are offset by half a row, so you have a top bump and a bottom bump.

Note: I am using red contrasting yarn for demonstration purposes only so you can see things better.

Active Time 10 minutes
Total Time 10 minutes


  1. 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.

    aligning the two pieced knitted in garter stitch so the cast on tail is on the right on each side
  2. Pull the yarn through the last stitch on the left side and then through the last stitch on the right side.

    pulling the yarn through the first stitches on each side with a tapestry needle
  3. 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.

    going through the first bottom bump on the edge of the first garter stitch ridge from right to left
  4. Go through the top bump at the end of the first ridge on the right side.

    going through a top bump at the edge of the first garter stitch ridge on the right side
  5. Then, pull the yarn through the bottom bump on the right side which is one ridge above.

    going through a bottom bump on the left side one ridge above

    Click on the link, if you don't know how to count rows in garter stitch.
  6. Pull your tapestry needle through the top bump on the right side, also one ridge above.
    going through a top bump on the edge of the right side once again
  7. Repeat steps 5+6 until you finished the seam.
    continuing seaming garter stitch with the mattress stitch
    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.
    joining knitted pieces in garter stitch together with the mattress stitch and someone pulling on the tail to close the seam


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.

holding the two parts you want to sew together between three fingers to make the seaming easier

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).

difference between top and bottom bump in garter stitch seaming

Further reads:

Anyway, that’s everything you need to know about seaming garter stitch. Comment below in case you still have any questions.

A step by step tutorial on how to seam garter stitch using the mattress stitch technique. It creates an almost invisible seam that lays flat, plus it's super easy to sew - even for beginners.

4 thoughts on “Seaming garter stitch for beginners”

  1. Hi Norman,
    I’m so glad I stumbled upon your blog. Best blog ever! Every question I have about knitting is answered here in your blog. Everything is clearly explained and your videos are very clear to understand. I love your free patterns, I can’t wait to knit one of them. Thanks again – from New Zealand 🙌

  2. I am finishing on a winter hat for my three-year-old Great Granddaughter. I sewed a seam together and I was very unhappy with the results, regardless of the care I took to do so. I found your site and LOVE it. Thank you so very, very much. This is the first time that I have used your Blog, but I WILL BE BACK.

    I will be using your site for my Go-To reference guide. Thank you so very much.

  3. Hi Norman, thank you so much for your blog! It has become my favourite knitting blog. You explain everything so nicely and I always feel happy after watching your videos! I was wondering if you could also explain how to seam seed stitch, so that the seam lays flat and the pattern continues seamlessly from one piece to another.

  4. I am trying to insert a sleeve into a jumper knitted in garter stitch. I am joining a vertical piece to a horizontal piece – so it’s different to what you’ve shown here (horizontal to horizontal) and much more difficult! Do you have any tips, videos to help? Thx.


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