To kitchener stitch a seam, begin by having both edges scrapped off with several rows of waste yarn. Then fold fabric in half, with the purl sides out and the waste yarn sandwiched in between the layers.
Begin stitching from the yarn tail side. Use a blunt nose needle to minimize yarn splitting. I’m using a contrasting (blue) yarn to highlight the stitches. Insert needle with the yarn tail into the bottom of the outermost stitch and bring it up through the outermost stitch on the other (top) side. Pull yarn through both stitches.
From the same (top) side, insert the needle into the next stitch from the top down.
At the same time, insert needle into the previously worked stitch of the other (bottom) side. Pull yarn through both stitches.
On the same side as last stitch (bottom), insert needle from the new stitch on the bottom side and into the previously worked stitch of the other (top) side. Pull yarn through both stitches.
From the last stitch worked on the same (top) side, insert needle into the next new stitch and into the previously worked stitch on the other (bottom) side. You will always have 2 yarn strands in each stitch.
Continue in this manner across the row, keeping your tension snug but not tight and trying to duplicate the original tension of your work. The folded over waste yarn helps to keep the tension even. You will soon get into a rhythm of ‘old/new, old/new’ on each side.
Finished row of grafting.
Turn work inside out with waste yarn on the outside. Notice your new row of stitches (in contrasting blue yarn).
Remove waste yarn and admire your perfectly grafted seam!
NOTE: When I graft a sock toe, I catch the knot of each stitch from the last row of each side before I start grafting the seam. This will close any holes that may have developed by stretching the yarn between the ribber and main bed and will minimize the ‘ears’ that may form. Do the same on the other side of the toe after completing the grafting and before tying off.
(slisen.blogspot.com)