Picking up stitches is necessary for creating an attached piece of knit fabric. A pattern will often direct you to “Pick up” (PU) or “Pick up and knit” (PU&K) – these are two different things.
Pick Up (PU) – Using a knitting needle but no yarn, insert the tip of the needle into existing stitches, slipping them onto the needle to create usable loops.
Pick Up & Knit (PU&K) – Using a knitting needle and a separate strand of yarn, insert the needle into the edge of the fabric, wrap the yarn around the tip of the needle and pull a loop through to create a new stitch. Repeat along the work.
A good rule of thumb for figuring how many stitches to pick up is to divide the rows per inch by the stitches per inch (rpi/spi = x). Pick up 1 stitch along the edge of the piece for every x rows. For example, if the gauge is 3 spi and 6 rpi = 1″, divide 6 by 3 to get 2. You would pick up 1 stitch along the edge of the piece for every 2 rows. When picking up stitches along a curved neck edge a few more stitches will be required to be picked up to give a graceful curve to the work, these can be decreased later to prevent too much fullness in the row.
Step 1: Insert needle into edge of right side of knitted piece, 1 stitch from the edge.
Step 2: Wrap the yarn around the tip of the needle and pull back through the stitch, creating a loop on the right hand needle. Work along the edge until the necessary number of stitches are picked up.