This tutorial explains how to sew a folded hem with almost invisible stitches, after bind off a project.
To sew the foled hem, you will need a yarnneedle and a length of yarn (at least equivalent to the length of the hem).
If the hem is really long, you may prefer to work with smaller lengthes of yarn to avoid making knots.
You will sew your hem to wrong side of a row (or round). Locate it. If needed, use multiple safety pin to mark it.
Pull the strand of yarn, from back to front, through the first bound off stitch.
Pull the strand of yarn through the 2nd bound off stitch, from front to back.
Pull the strand of yarn through a bump on the wrong side of a stitch, from top to bottom. Tighten (but not too much).
Repeat steps 1 to 3, making sure you are attaching the hem to the back of stitches from the same row (or round).
On the wrong side
On the right side