The Mattress Stitch – How To Seam Knitting


In this post, you will see how to seam knitting using the mattress stitch.

Using the mattress stitch is my preferred method of sewing up knitting.

The mattress stitch technique allows you to seam your knitted pieces so that they have an invisible seam.

The mattress stitch - how to seam knitting

Using The Mattress Stitch For An Invisible Seam

When you sew your knitting you will use a matching color which makes it easier to hide the seams.

In the tutorial and instruction photos, I have used yarn in a contrasting color, so that you can see the live stitches.

If you are knitting with a yarn that is really thick like super bulky/super chunky/14 Ply yarn then you can use yarn in the same color but in a /chunky/12 Ply/bulky yarn instead.

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sewing up knitting using the mattress stitch
How to seam a flat knit hat – video tutorial

Sewing Up Knitting

I know that not all knitters like to seam but when you have to, this stitch makes it quite easy to get a really good finish.

Normally when sewing up a hat or sweater this finishing technique is preferred because you can’t see the join clearly.

Many garments are knit flat and then seamed, from the shoulder seams to the side seams and the sleeves. 

seaming knitting

What Does Mattress Stitch Mean In Knitting?

The main technique of the mattress stitch seam is very simple, you work in the direction that the piece was knitted in (vertical seams) and join the pieces together with the right sides facing you.

You do this by sewing through one bar between the knit stitches on one side of a knitted piece and then a corresponding bar on the opposite side of the other knitted piece.

There are two slightly different techniques needed for seaming up garter stitch and stockinette stitch.

In this tutorial, you will see step-by-step photographs showing you how to seam Irish moss stitch.

There are also links to video tutorials below that will help you with seaming stockinette stitch and garter stitch.

Step 7 side seams
Image of a stocking stitch garment side seam.

Time needed: 1 day, 10 hours and 30 minutes

How To Seam Using The Mattress Stitch

  1. Thread the darning needle and insert it into the first stitch.

    Thread your darning needle/yarn needle with your strand of yarn – either use the tail left on the knitted fabric from the cast-on or cut a new length of yarn.
    The length of the yarn may be longer depending on the length of the seam.
    (Please note, I have used a contrasting yarn for demonstration purposes)
    Push the needle through the left-hand corner of the yarn between the 1st and 2nd stitch on the first-row edge stitches of the knitting.Mattress Stitch Step 1

  2. Pull the yarn through and insert the needle into the piece you are joining.

    Pull the yarn through the first piece of knitting and insert your darning needle into the second piece you are joining.
    The needle should go into the horizontal bar of the 1st and 2nd stitch on the other piece.
    Make sure to stay along the same column of stitches.
    Then pull your tail/yarn through.Mattress Stitch Step 2

  3. Repeat steps 1 and 2

    Continue to push your needle through the next 2 bars on the left-hand piece of knitting.
    Pull the needle and yarn through.
    Then go back over to the right-hand piece that you are joining and push the needle through the opposite 2 bars and pull the needle and yarn through.
    The side edges are connected with the mattress seam.Mattress Stitch Step 3

  4. Continue to do this on both sides of your knitted pieces to create a ladder.

    Continue to seam in this way up both sides of your knitted pieces.
    You will see how this creates a ladder of sorts that joins the pieces together.
    When you have worked around 1 inch of this seaming you can then move on to the next step.
    (*In the photo below I seamed more than 1 inch for the tutorial)Mattress Stitch Step 4

  5. Pull the yarn to close the seam.

    In the next step, you will pull the yarn you are seaming with to close the gap.
    Hold both the tail/yarn and the start of the work and slowly pull the yarn to close that gap.
    Don’t pull too tightly or you will gather up your knitting.
    The seam should lie flat and your seaming yarn should not be visible.
    This leaves you with a neat seam. Mattress Stitch Step 5

  6. Check the wrong side.

    You can check the wrong side of the work to see how the seam looks on the inside.
    The sturdy seam is flat and hidden on the right side.
    On the inside (the wrong side of the work) you will see the inside seam. Mattress Stitch Step 6

  7. Continue to seam using the mattress stitch.

    Continue to seam your work in this way for about an inch then pull the yarn to close the seam until your two pieces have been joined together.
    Your seams should be perfectly aligned.
    If this does not happen, you may have to unpick and seam again.
    Once the seaming is complete, both seams should look neat and the fabric should lie flat, finally, at the end of the seam, you can weave in any loose ends. Mattress Stitch Step 7

Other Methods To Sew Your Knitting Pieces

If the mattress stitch is not your ideal method you can try other seaming methods

The Kitchener stitch method 

The Kitchener stitch is great for all patterns and provides an invisible horizontal seam.

A tapestry needle is needed.

The Finchley Graft method

The Finchley Graft method is similar to the Kitchener stitch but you work it on the wrong side of the fabric.

Three-needle bind-off method

Three-needle-bind-off is ideal for garments, especially shoulder seams and underarm seams as it provides structure. 

Plus you can use your knitting needles, no sewing needle or tapestry needle is needed.

Pick up and knit method

The pick-up and knit method is perfect for a top-down sweater pattern or other patterns like shawls.

Plus you can use your knitting needles, no sewing needle or tapestry needle is needed.

Back stitch method

The back stitch provides a strong fabric and it’s great for garments.

Whip stitch method

The whip stitch is the perfect seaming method for a new maker but it doesn’t provide the best results as you can see the seam.

Slip stitch crochet method 

The slip stitch is ideal for you if you know how to crochet as well. 

All you need is your crochet hook.

How To Seam Stockinette Stitch

In this video tutorial below from Berroco Knit Bits, you will learn how to seam together two pieces of knitting in stockinette stitch.

How To Seam Garter Stitch

In this video tutorial from Knit Purl Hunter, you will learn how to seam together two pieces of knitting in garter stitch.

If you are new to knitting and want to learn more, please take a look at my free knitting lessons and video tutorials on my YouTube channel.

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