To make a rib knit stitch, you'll need to alternate equal amounts of knitting and purling on the same row. You must keep knitting the knit stitches and purling the purl stitches on subsequent rows to achieve the length of the ribbing pattern you need or want. Your needle size and yarn type will affect how much stretch your rib knit stitch has. In order to make a rib knit stitch, you will have to know how to create knitting and purling stitches as well as casting on and off techniques.
It's first necessary to cast on as many stitches as you'll need in your rib stitch pattern. Casting on is done by hand by placing an even row of yarn loops on one knitting needle. You can then start your rib knit stitch pattern by knitting two cast on stitches and purling the next two. When starting to make a knit stitch by placing the point of the empty needle up and into the top yarn loop on the other knitting needle, it's important to have the yarn strand behind the needle. When making a purl stitch, the yarn strand should always be in front of the needle.
Making ribbing by knitting two stitches, purling two and continuing on this pattern is known as a "2 x 2 rib." If instead, you were to create a rib knit stitch by knitting one, purling one and continuing on this pattern, you'd be making a "1 x 1 rib." Sweater patterns will specify the kind of rib required for the sleeve cuffs, bottom edge and neckline. Typically, the same rib stitch is used for the entire garment with a needle size one or two times smaller than that used for the body of the knitted sweater. When you've completed your rib stitch rows, you will either change to larger needles and a different knitting pattern or cast off by working two stitches at a time and pulling the first loop over the second by hand until the row is complete.
In general, the bigger the needle size, the less stretch the rib knit stitch pattern will have. Using large knitting needles and bulky weight, or two strands of worsted, yarn in a rib stitch is popular for making scarves. Since the ribbing is reversible, meaning the pattern looks the same on both sides, it works well for an attractive scarf. A rib stitch is the third most common stitch after the garter and the stockinette. The garter stitch pattern is made by knitting every row, while the stockinette is created by alternating knit and purl rows.
