How to Use the Mattress Stitch
Hold two squares together so that the loops are offset, matching a “bump” with a “dimple” so that they will be nested together when joined.
Thread seaming yarn on a tapestry needle. Pass the threaded needle through the corner loop of both layers from front to back, then pass through again to secure.
Pass from the wrong side (inside) to the right side (outside) of one square through one half of an edge loop, then pass back to the wrong side through the second half of the loop. Repeat with the other square, moving back and forth between the squares in a zigzag.
How to Seam with the Mattress Stitch
If you are like me, seaming my crochet projects can be the most intimidating part of the entire pattern. Do I use a slip stitch seam, whipstitch, mattress stitch? Some patterns will specify the type of seam used, but sometimes I disagree because of my gauge, yarn, or the look I am going for. Many pattern simply instruct you to seam, and don't tell you which seaming method to use.
Interweave Crochet Home includes and excellent how to crochet section that shows you not only how to work some of the more basic crochet stitches but also how to seam and block. And one commonly used seaming technique is the mattress stitch. Here is an excerpt from Interweave Crochet Home to show you how.
Mattress stitch is excellent for joining garment pieces. Lay garment pieces side by side, RS up. Cut a length of yarn as long as your arm and thread onto tapestry needle.
To secure the end, insert the needle from the top of right side to the back and from the back of left side to the top (1) .
Repeat to create a tiny stitch.
Working ½ stitch in from edge, insert needle into right side, from front to back, and push needle from back to front to emerge about ½ inch away (2).
Insert needle into left side parallel to the point where needle emerged on right side, from front to back, and push needle from back to front about ½ inch away (3).
Continue alternating right and left sides, weaving the seaming yarn from side to side (4) and (5).
After about six stitches, pull the end of the seaming yarn to draw stitches taut, but not so tight that they pucker the seam. The seaming yarn disappears (6)!
Continue sewing and occasionally pulling taut the seaming yarn until pieces are joined.
Use this seaming technique to join crochet afghans squares, seam your crochet cardigan pieces together, or any other pieces you can imagine and crochet. For great crochet home decor projects to practice your seaming with and more great how-to crochet information, get your copy of Interweave Crochet Home. Check out the great projects!
P.S. Do you have a favorite seaming technique? Share it in the comments.