The Mattress Stitch is a finishing technique for vertical seaming on knitted pieces.
The technique creates an invisible join between pieces worked in stockinette stitch, garter stitch or ribbing, perfect for so many things, such as sewing the front and back of a sweater together or two square pieces to assemble a knitted blanket.
How to sew two knitted pieces together?
Step by step explanations for Mattress Stitch
To do this, you will need to use the same thickness of yarn as the one used for the
project, neither thinner nor thicker.
First, line up the two parts you want to sew. Pass your threaded tapestry needle from the back of your work to the front, where you want to start your seam.
For Mattress Stitch, you sew two pieces of knit fabric together through a strand of knitted yarn on each side, alternating back and forth, working vertically along the edges. The strand of yarn you grab is a horizontal bar that runs between the stockinette (or “V”) stitches. If you pull gently along the right and left edges of your knitting, you can see these horizontal bars (or “ladder”) between the “V”s.
Pass the needle between the bars of the first “V” from the back of your work to the front.
Then pass the needle through the bar of the V from under the bar in the center of the V.
Continue working vertically along both edges, passing the tapestry needle under each bar of each piece.
To close the seam, gently pull the length of thread from the top or bottom. If you are working on a long seam, it is better to sew a few inches, then pull to close, sew a few inches again and pull, continuing in this manner to the end of the seam, making sure to maintain a constant tension throughout.
For garter stitch, you proceed exactly the same way except that you pass your needle under the garter ridge.