I don’t think it’s any secret that I love to crochet blankets and granny squares. (if you need further evidence, you may enjoy my free crochet pattern for the Mod 9-Patch Blanket.) I’ve experimented with many different joining techniques and to be honest, I don’t have a favorite. Today, I’m sharing one way to easily join granny squares (or any other crochet or knitting project that needs to be seamed) by using the mattress stitch with both a photo and a video tutorial.

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For the mattress stitch, you’ll need a yarn needle, which is a blunt needle with a very large eye that yarn can easily be threaded into.

I use yarn needles regularly, for weaving in ends and seaming, and my favorites are bent tip needles from Clover, such as the Clover Chibi Jumbo Darning Needle set (which comes with a little carrying case). These needles work great for light (also known as #3 or DK yarn) through jumbo (also known as #7 or roving yarn), but if you are using thinner yarns, you’ll need a thinner needle so your stitches don’t stretch out. Personally, I prefer metal to plastic needles, which sometimes snap (or worse, snag on the yarn!).

Tutorial: How to join with a mattress stitch seam

You can watch the video version of this tutorial (on a knit hat) below, or scroll down for the photo tutorial (on crocheted granny squares).

If you can’t see the video tutorial above, click here to watch it on YouTube.

Step 1: Thread the yarn needle (preferably with the yarn tail of one piece).

When I plan to seam with the mattress stitch, before fastening off, I generally leave a yarn tail that is about 3 times longer than the piece I plan to seam. This gives me room to work comfortably and still weave in ends later to secure my project from unraveling.

Step 2: Start with the pieces right side up/with wrong sides together.

In this case, I’m starting with the yarn tail from the piece on the left.

Step 3: Insert the needle into the first stitch on the opposite piece.

Since I’m using the yarn from the left piece, I inserted the needle into the front loop of the stitch on the right. You can also insert the needle under both loops if you prefer. Your needle should be moving from the outside of the piece towards the seam and the other piece.

Step 4: Insert the needle into the corresponding stitch on the original piece.

In my example, I inserted the needle into the front loop of the first stitch on the left piece. Again, the needle should be moving from the outside of the piece towards the seam and the other piece.

Step 5: Insert the needle into the next stitch on the opposite piece.

Continue to work from the outside towards the seam and the other piece.

Step 6: Insert the needle into the corresponding stitch on the original piece.

Do your best to line up stitches on both sides to avoid puckering.

Continue repeating Step 5 & 6 until your seam is finished!

After your seam is finished, weave in the yarn tail on the wrong side of your project to secure it from unraveling.

Now that you’ve learned the mattress stitch, you may want to try it out on some granny squares right away! For project inspiration, follow my Crochet Motif Patterns – Squares board on Pinterest.

What’s your favorite method for joining granny squares? Here are some other options that I love.

• How to join with slip stitch seam
• How to join with a single crochet seam
• How to join with a whipstitch seam