Cast on Definition 1 of 3Pro Tip 1/3Knitting Start Used specifically for the initial step in knitting projects. I learned to cast on twenty stitches to begin my scarf. Pro Tip 2/3Not Removing 'Cast on' involves adding loops, not taking them off the needle. Be sure not to drop any stitches when you cast on. Pro Tip 3/3Method Variation There are several ways to cast on, like the thumb or cable cast-on. My grandma taught me her favorite way to cast on for knitting.