Knitting Seams with the Mattress Stitch Like a Pro

“It’s all in the finishing.” How many times have you heard that? It’s true, though, finishing can make all the difference. That’s where the mattress stitch comes in!

Garter stitch selvage edge, an example of using the mattress stitch in knitted seams.

Garter stitch selvage edge.

My favorite knitting technique for making beautiful finished garments and the one I use almost exclusively (that means “all the time” unless a pattern specifically recommends another method!) is the mattress stitch. I have no idea why this seaming process is called the “mattress stitch”; if any of you know, please leave a comment!

Preparing to Seam

It’s important to have a good selvage edge. When I learned to knit, a smart, experienced knitter told me to always knit the first and last stitch of every row. This makes a garter stitch selvage edge which is easy to see when you’re seaming. You don’t have to add extra stitches, just knit the first and last stitch no matter what the pattern is. If I’m knitting a P2/K2 rib, I just knit the first stitch then knit 1, purl 2, knit 2, and so on.

Before you begin seaming, you should block all of your pieces so the selvage edge is easily accessible. I usually use a steamer to block my garments, but some folks swear by wet blocking, too, so use whichever method you like best.

I usually seam a garment with the same yarn I use to knit it. However, if the yarn used in the knitting is not quite suitable for seaming (like a novelty yarn, a yarn that pulls apart easily, or a bulky yarn) you might need to use something else. I find that Cascade 220 comes in a wide enough range of colors to suit. If you’re working on a lightweight piece and need thinner yarn for seaming, try using embroidery thread. The color range is endless and the thread is really strong. Some folks also use one or two plies of the garment yarn to seam, which I think is a neat idea.

Knitting Seams Together: Mattress Stitch Made Easy

One of my favorite knitters, Kathy Veeza ( a.k.a “Grumperina”), wrote a wonderful article in the spring 2008 Knitscene, which you can download now!), all about seaming. This is just the mattress stitch portion, so check out the entire article on the Knitscene 2007-2009 Collection CD. I took the photos—I think they’re a good example of how mattress stitch works as well on ribbing and moss stitch as it does on stockinette stitch (and garter stitch, and seed stitch, and whatever stitch you’re working with!).

Step 1 of knitting seams together with the mattress stitch.

Step 1 in knitting seams together with the mattress stitch.

Step 2 of knitting seams together with the mattress stitch.

Step 2 in knitting seams together with the mattress stitch.

Finished seam. To bring the knitted seam together, simply pull gently on the yarn and the seam will tighten up and disappear.

Finished seam. To bring the knitted seam together, simply pull gently on the yarn and the seam will tighten up and disappear.

With the right side of the knitting facing you, use a threaded needle to pick up 1 bar between the first 2 stitches on one piece, then the corresponding bar plus the bar above it on the other piece (Step 1). *Pick up the next 2 bars on the first piece, then the next 2 bars on the other (Step 2). Repeat from * to the end of the seam, finishing by picking up the last bar (or pair of bars) at the top of the first piece.

The secret to streamlined seams is always working mattress stitch from the same vertical column. Never veer to the right or left of the seaming line—the stitch adjacent to the seam should be fully visible from base to top along the whole seam. If you veer into that stitch or farther away from it as you seam, your seam will zigzag in a distracting way. When seaming a sleeve into an armhole, make sure to follow this rule on the body pieces.

The most important step to making perfect knit seams comes after the sewing is done. I know you’re dying to show off your new sweater, but investing just a few more minutes will make everything look absolutely professional. After weaving in all the ends, you might notice that the seams of your sweater are a bit bulky, especially when compared to the smooth, sleek fabric of the stockinette portions. Reblocking the finished sweater for the sole purpose of flattening the seams is time consuming and unnecessary. Instead, moisten the seams by spraying them with a water bottle or by laying a damp towel on top of them and then smooth the fabric by patting it down with your fingers. You may also lightly steam the seams to achieve the same result, taking the utmost care if your sweater is wool.

Knitting finished, pieces seamed, and seams streamlined: now you’re ready to show everyone your new sweater, proudly announcing that  yes, you knit it yourself—thoughtfully, methodically, lovingly, and with seams that will stand up to scrutiny every time you look in the mirror.

Kathy Veeza blogs and shares her knitting expertise online as Grumperina.

I hope this little tutorial helps you achieve the perfect seam!


One Comment

  1. linda r at 2:11 pm February 18, 2018

    Nice instructions. I think mattress stitch came from the days of hand stitching mattresses together. I heard this quite a few years ago

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