Also on these boards
How-To: Kitchener Stitch for Joining Seams in Knitting #knitting
How to Join in the Round Invisibly To join in the round invisibly, cast on one more stitch than your pattern calls for. Then, when you’re ready to join in the round, slip this extra stitch to the left needle. Using the working yarn and the yarn tail held together, knit the first two stitches together. Now drop the tail and knit as you normally would.
Knitting Tutorial - Matress Stitch worked horizontally to join two pieces of knitting. The stitches are in contrasting color to show detail, but I'd love to do this and add some embroidery for embellished seams on a sweater. from Knitting Daily