The Double Cast-On
The foundation row of a knitted fabric is called the cast-on row. This row provides the base upon which rows of stitches are built. There are many ways to cast on stitches, but my favorite and the one I use most often is the double cast-on, also known as the long tail cast-on. It is multi-purpose and forms a firm, yet elastic edge.
Unwind a length of yarn estimating how much will be necessary for the required number of stitches. When making garment pieces or items which are seamed, leave extra yarn to tie into a loose knot after casting on. This extra length can be used for seaming.
To begin with make a slip knot. The shorter length of yarn should be on your left and the ball of yarn to your right. Holding the length of yarn in your left hand, wrap the yarn from the ball clockwise around your index twice. Pull the loop of ball yarn through the loop of tail yarn around your finger. Drop the yarn off the fingers, and gently pull the end of ball yarn to form the slip knot. Slide the slip knot onto a knitting needle, pulling on both yarn ends to tighten. The loop should slide easily along the needle.
A lot of knitting books describe a double cast-on using both the left thumb and index finger. I find this method cumbersome for beginners, and the same result is achieved with a modified version. To cast-on use the extra length of yarn dangling on your left, and slip your index finger or thumb (I like using my index) under this end of yarn making a partial loop. With the needle in your right hand, take the needle point and slide through the partial loop. Wrap the ball yarn around the needle clockwise. Slide loop from forefinger over the needle tip and pull on the tail and ball yarn ends to create a stitch. Neaten the stitch by pulling gently so the stitch slides easily across the needle. Do not pull too tight or too loose. Try to cast-on loosely or you will find it difficult to insert the needle. Repeat this step till you have the required number of stitches on your needle, spacing them evenly. When finished tie up the extra yarn for seaming or weaving in.
This is a necessary cast-on when adding stitches to a fabric in progress, but can be used as a foundation row. Because two needles are used, I find it takes longer to cast-on stitches than a double cast-on for the foundation row. It forms a firm, elastic edge. For the foundation row, make a slip knot and place on left needle. Insert right needle through slip knot and wrap yarn around right needle. Pull a loop through without dropping, then insert left needle front to back through the loop and place on left needle (twisting the stitch). Insert the right needle between the two stitches on the left needle. Wrap the yarn around the right needle as if to knit, pulling the yarn through to make a new stitch. Do not drop the old stitch off the left needle, transferring the new stitch to the left needle by inserting the left needle into the front of this loop as shown. Repeat, always inserting the right needle between the last two stitches on the left needle until the required number of stitches are cast on. Do not pull tight or it is difficult to insert the needle. Maintain an even, consistent tension.
Cast-ons take practice to maintain an even tension, but loose enough to insert your needle.