Normally, dropping stitches is considered a bad thing in knitting. When you drop a stitch, you've made a mistake, and a hole or a run is the result.
You can, however, use the look of a dropped stitch on purpose to make a fun design. It's easy to do and makes a great look for accessories and other items that don't have to be solid.
Making a Dropped Stitch
It is easy to incorporate dropped stitches into your knitting. To make a dropped stitch, act as if you are going to make a knit or purl stitch as normal, but instead of just wrapping the yarn around the needle once, wrap it two or three times.
If you're working from a pattern, it will tell you how many times to wrap the yarn around. If you're working up something on your own, you can experiment, but know that the more times you wrap a stitch, the more elongated it will become.
Repeat this procedure on each stitch across the row, or as the pattern indicates. When you get to the next row, just knit or purl the stitch and slide the extra wraps off the needle. When you get to the end of this row, give the work a gentle tug to straighten out the dropped stitches.
A row of dropped stitches looks like long knit stitches and gives an open look to your work.
Using Dropped Stitches
Dropped stitches are a fun addition to a lot of projects, including scarves, belts, headbands, and tank tops. They would make a fun washcloth or summer hat.
Patterns that use dropped stitches generally have you knit a couple of plain rows on either side of the dropped stitch row to add stability and structure to the finished piece.
One popular stitch pattern that uses dropped stitches is known as seafoam stitch. It's worked by wrapping different stitches a different number of times across the row. This gives the finished fabric an open, wavy appearance that is very popular for scarves. There are many variations of the theme available on Ravelry.
You can also add dropped stitches as a design element to make a plain project a little more interesting, such as on a lightweight Stockinette sweater. You will want to make a gauge swatch and determine how the drop stitches alter the gauge of the fabric so you don't end up with a much larger sweater or project than what you intended.
Another option when it comes to dropping stitches is to work the stitches as normal through the project, then at some point in the project, you allow stitches to drop off the needle and run back to the cast on or wherever the stitches started. This leaves the running strands of yarn visible and significantly widens a project.
Knitting is all about using your imagination to make unique knitted items, so don't be afraid to drop some stitches on purpose.