crafts & knitting · knitting tips

A mattress stitch tutorial

Seaming. You either love it or hate it. Personally I’m a lover of seams, especially mattress stitch because it gives such a professional finish, so I thought I’d write a little about the benefits of using a mattress stitch seam and how best to work it on different knitted surfaces.

Granted, there are times when a seam is not always appropriate. Socks for instance are definitely better without seams but when it comes to toy knitting I’m a firm believer in seams as an integral part of shaping the finished toy.

It seems that for some seams are dreaded and actively disliked and perhaps the main reason is because seaming takes longer and after you’ve finished knitting something you don’t want to spend ages finishing it off. However, I suspect that there are some who don’t like seaming because they are never happy with the results. To those people I’d like to offer the following few little tips from my experiences and a few words of encouragement; you can do it, keep at it because practice really does make for perfect seams…

So what is mattress stitch?

It’s a way of joining a vertical seam with a virtually invisible look on the front of the work, on the reverse there will be a raised selvedge, see here the front and back of a mattress seam:

front and back

The principles of mattress stitch are very simple, you work in the direction that the piece was knitted in and join the pieces together with right sides facing you, by sewing through one bar between stitches on one side of a seam and then a corresponding bar on the opposite side of the seam. When I say ‘bar between stitches’ this is what I mean:

In the picture below you can see I have numbered the 3 columns of stitches nearest to the edge of the work. Each single stitch makes a neat V shape with each row of stitches sitting neatly in the V of the stitch in the row below to create columns. Between every column of V shaped stitches there are horizontal bars running from the back of one stitch to the next (on the reverse of the work this is seen as a purl bump). These ‘bars’ between stitches are what you want to be sewing through when you work mattress stitch, it’s commonly referred to as a ‘channel between stitches’ and the best channel to use is the one between stitch 1 (which is right on the edge of the work) and stitch 2, as shown here. Some people seam through 2 bars each time, now if you have a very long length to join this is probably a good choice but as all my patterns deal with small pieces I always seam through a single bar as I feel it gives a neater seam on most knitted fabrics.

channels2

What to sew with:

Before you begin, it’s best to consider what you are going to sew your seam with and whether you are going to use the cast on tail end from the knitted piece or use a new length of yarn.

Usually I begin seaming with the cast on tail from the work (all of my patterns give instruction to leave a certain length of yarn when you cast on) but sometimes there are reasons why you might not want to do this:

  1. the tail end you’ve left is too short
  2. the yarn is not strong enough *
  3. the yarn is expensive and you don’t want to use it up on a seam.

In these instances you would cut a length of alternative yarn to seam with. This could either be a length of the same yarn your piece is knitted in or one of a similar colour.

*Going back briefly to point 2 above. If you have knitted in a single ply yarn or a softly plied wool you might find that the yarn breaks too easily to be used to sew a seam. I love knitting animals in Malabrigo worsted which is a single ply yarn but I’ve often found that half way up a seam the yarn just comes apart and then you have to unpick the seam and start again. You can strengthen any weak yarn by giving it extra twist. Do this by simply threading the needle with the tail end and twisting in the same direction as the yarn is plied until the yarn curls on itself. This will now be a much stronger yarn to seam with:

snapped

So back to seaming. Whether you use the cast on tail or a new length of yarn you need to begin by anchoring the bottom of the seam.

Anchoring the seam:

I always lead with piece on the right hand side of the seam, it seems to give a neater finish (but that could just be because I am right-handed), so here’s how to set up so your first seam stitch is on the right hand side of the seam…

Assuming you are starting with the tail from the left hand piece:

1, take the yarn across to the right hand piece and sew downwards through a stitch on the cast on edge;

2, now sew upwards through the corresponding stitch on the left hand piece.

If your tail end is on the right hand piece just follow step 2 above.

begin

Now you are ready to start the seam with the first stitch on the right hand of the seam and below are instructions for seaming 4 different surfaces:

1. Seaming smooth stocking stitch:

Making sure that you are working into the very first bar above the cast on edge, slide the tip of your needle through the bar between the first and second stitches…

stockingstitch right

(note: I’ve used blue yarn as the working yarn here simply for contrast so you can see more clearly, in reality it’s best to use colour as similar to the work as possible)

… then slide the needle through the corresponding bar on the left hand piece

st stitch left

Keep working up along the length of the seam, alternating between the right hand side and the left. At this point it does not matter if the stitches are loose (see below).

loose stocking stitch

Every inch or so you can pull gently on the working yarn to tighten then and draw the sides of the seam neatly together…

st stitch

Unless otherwise instructed don’t pull too tightly or the seam will pucker and become rigid (sometimes this will be useful depending on what you are seaming). If you find you have pulled too tightly you can gently lengthen the seam again, as mattress stitch forms a very fluid seam which will compress or stretch as required until you’ve tied it off at the end.

Once you have completely joined the sides it’s best to tie off the end you’ve sewn with (to the cast off tail from the knitted piece) in order to anchor the seam. Then weave in the ends (I usually weave them in along the seam selvedge although bear in mind that depending on the yarn you’ve used this can make the seam a little bulkier).

2. Seaming stripes on stocking stitch:

Seaming stripes follows exactly the same process as above. The main issue is making sure that the stripes line up nicely. I find that leading with the right hand side gives the neatest alignment, so just make sure that you are sewing the first stitch of a new colour section through the right hand side before the left.

stripes

straight stripes

3. Seaming reverse stocking stitch:

This is a little more complicated, but only because on one side of the seam you want to sew through the top part of a stitch and on the opposite side you’ll need to sew through the lower part. I’ve heard these referred to as ‘frowns’ and ‘smiles’, ‘mountains’ and ‘valleys’, ‘uppers’ and ‘downers’ and so on, you get the idea. Here’s a picture to show what I mean: 1 is a lower bar (smile, valley, u, etc.) and 2 is an upper bar (mountain, frown, n etc)

uppers and downers

In order to seam reverse stocking stitch all you need to do is be consistent. I tend to use the lower bar for the right hand side of the seam and the upper bar for the left hand side but it doesn’t matter which side you chose as the ‘upper’ and which as the ‘lower’, all that matters is that you are consistent once you have chosen.

Begin as above by anchoring the start of the seam and then beginning with the right hand side slide the tip of the needle through the first lower bar…

lower right

and then on the left side slide the tip through the corresponding row upper bar…

upper left

Work the length of the seam, alternating between the right hand side and the left. At this point it does not matter if the stitches are loose (see below).

rev stocking stitch loose

Every inch or so you can pull gently on the working yarn to tighten then and draw the sides of the seam neatly together…

rev stocking stitch

Unless otherwise instructed don’t pull too tightly or the seam will pucker and become rigid (sometimes this will be useful depending on what you are seaming). If you find you have pulled too tightly you can gently lengthen the seam again, as mattress stitch forms a very fluid seam which will compress or stretch as required until you’ve tied it off at the end.

Once you have completely joined the sides it’s best to tie off the end you’ve sewn with (to the cast off end from the piece) in order to anchor the seam and then weave in the ends (I usually weave them in along the seam selvedge although bear in mind that depending on the yarn you’ve used this can make the seam a little bulkier).

4. Seaming garter stitch:

In garter stitch every row is knitted, forming distinct purl ridges across the fabric. When seaming garter stitch I don’t sew through the stitches on every row. Instead I ignore the bars on alternate ‘smooth’ rows and just sew through stitches on the ‘bumpy’ rows. I’ve found this gives a much neater seam. Here’s a seam joined by sewing through a stitch from every row (both purl bumps on one row and smooth bars on the following row), it looks messy to me:

garter stitch wrong

And here’s a seam sewn by just using the stitches from the alternate ‘bumpy’ rows, which I think looks neater:

garterstitch right

Simply use the same principles as for seaming reverse stocking stitch by sewing through upper bars on one side of the seam and lower bars on the other. Here I’ve sewn through the lower bar on the right hand side…

garter rightside

And the upper bar on the left-hand side…

garter left

Unless otherwise instructed don’t pull too tightly or the seam will pucker and become rigid (sometimes this will be useful depending on what you are seaming). If you find you have pulled too tightly you can gently lengthen the seam again, as mattress stitch forms a very fluid seam which will compress or stretch as required until you’ve tied it off at the end.

Once you have completely joined the sides it’s best to tie off the end you’ve sewn with (to the cast off end from the piece) in order to anchor the seam and then weave in the ends (I usually weave them in along the seam selvedge although bear in mind that depending on the yarn you’ve used this can make the seam a little bulkier).

Remedying possible problems:

Jumping channels:

Sometimes if your mind is wandering you can accidentally jump across channels between stitches. This will be very evident on the front of the work, here there is a noticeable step on the left hand side of the seam (see where the arrow is pointing to). It’s easy to fix this by unpicking the work to the point just beneath the jump, see ‘Unpicking in the event of a mistake’ below.

jump channels

Out of alignment stripes/colour work:

When sewing stripes it’s obviously important that they line up. Again I find that leading with the right hand side usually gives the best result. If you find you’ve missed a loop or your stripes are not aligned then it’s best to pull out the seam and start again (see ‘unpicking in the event of a mistake’ below).

not aligned

Sewing in the wrong channel between stitches (not making a neat V):

Sometimes you may accidentally sew through the bar in the centre V of a stitch instead of the bar between two stitches. This is what that seam will look like. You can see that the stitches immediately on the left of the seam are lying in the same direction as those on the right of the seam rather than mirroring them, so it looks like the central row of stitches has two left hand arms. It’s a neat seam but not invisible and to correct this you’ll need to unpick the seam and start it again  (see ‘unpicking in the event of a mistake’ below).

half channel

Unpicking in the event of a mistake:

One of the nice things about a mattress stitch seam is the ease with which it can be undone.

If you turn the work so that the wrong side is facing you’ll see the selvedge seam. Bending that over you’ll be able to see a little line of straight stitches running down the length of the seam these are the back of the mattress stitches (here I’ve used blue thread for contrast). Simply find the point that you need to unpick to and slide the tip of the needle underneath the stitch at that point and pull the working thread gently all the way through so unravelling all of the mattress stitches above that point. Then just re-thread your needle and continue seaming.

pull out

Well, that’s it. I hope you find some of these tips useful and enjoy using them to finish your knitted projects neatly and professionally. If you have any questions ask away in the comments below and I’ll do my best to answer them and if you have anything else you’d like me to cover in a future tutorial please let me know.

happy knitting and seaming 🙂

You can find my other tutorials here

58 thoughts on “A mattress stitch tutorial

  1. I love seaming and find it quite relaxing I have never seamed garter stitch and your tutorial is brilliant so clear and lovely photography. I have yet to knit a little cotton rabbit but am inspired to start now xx thank you😍❤️❤️

  2. Thanks a lot for this great tutorial! I’ve always failed to produce nice seams and this is why I prefer knitting in the round, even if it’s very fiddly with small pieces!

  3. Thank you for the very good tutorial. I would love it if at some point you could address attaching arms and legs.

  4. Hi Julie:
    Thank you so much. Your tutorial has helped me really improve my mattress stitching. I’ve searched the internet to find a tutorial that explains how to end the mattress stitch seam at the bind off edge, and haven’t found one. What do we do? After stitching through the last ladder, it seems that the bind off edges should be woven together so it looks good too. Can you help us with that? Also, someday, it would be great to know how to transition from stockinette to garter and then back to stockinette. Mine always turns out a little messy. Love, love, love, all of your patterns! Best wishes to you and yours.

  5. Wonderful tutorial, I have struggled with mattress stitch, never turned out how it was meant to be. I followed your tutorial and my seam was perfect!!!!!.. Thank you so much

  6. at first thanks you very much because you provide every information very well. its very fantastic. you explain it so well. its a wonderful tutorial,that help every persons.its improve my mattress stitching.

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