Things You'll Need
Double-pointed or circular needles
Knitting in the round is a way for knitters to create seamless tubes of knit fabric for items such as caps, socks, sleeves and sweater bodies. You can knit in the round on a set of four or five double-pointed needles or on a circular needle. Picking up stitches is a way to extend a project from its finished edge to make it longer or to shape a project around odd spaces, such as a sock heel. Take special care in edges that have both knit and purled stitches as they are picked up differently.
Picking Up Knit Stitches
Hold the knitted fabric's edge where you need to pick up stitches and stretch it gently to locate the "V" that forms each stitch. The front of the work should be facing you. You will be pulling from the row that starts immediately below the bound edge.
Work from right to left, inserting the needle held in the right hand inside the first stitch that appears. Force the tip under the rightmost "leg" of the V and slide the loop onto your needle and be sure not to add bulk by knitting the picked-up stitch.
Continue to pick up stitches as needed by moving from right to left along the edge and pushing the new loops down the right-hand needle. Do not allow them to drop off the other end of your double-pointed needle or circular needle. If working with a set of double-pointed needles, shift stitches to empty needles as needed.
Pick up as many stitches as the pattern calls for or until you get to the edge of a row--whichever is relevant.
Work the picked-up stitches by pushing the series towards the tip of the left-hand needle so that the first stitch you will knit is the first one you picked up.
Picking Up Purl Stitches
Pick up any purl stitches that appear in your fabric by turning the edge to reveal the wrong side of the work. Do this while the front of your work is still facing you: simply roll the edge back to view the reverse side where the purl stitches appear as knit stitches, but do not turn the whole work over.
Insert the tip of the right-hand needle through the left leg of a purl's V on the reverse side from right to left. When you turn your work back up, the loop that appears on the needle will have a horizontal bar in front of it.
Work from right to left picking up loops as needed for your pattern as above. You can pick up both knit and purled stitches as they appear if you need to maintain ribbing or other pattern features.
Be sure the yarn of your project and the yarn you're using to work the picked-up stitches is from the same lot, or else your work may have subtle color changes where they are not desired.