First, there is only ONE sewing stitch involved with this
project; the blind stitch. Second, it's a stitch you have probably already used
in your crochet life. Here's how it's done:
Stitch the bag to the plastic canvas with two
1/4-inch deep stitches. This will anchor your yarn.
Move 1/4 inch along the hem and stitch through
both the bag and plastic canvas, taking care to not poke the needle and yarn
through to the right side of the work. Go 1/4 inch further and make another
stitch the same way.
Stitch around the entire border of the bag,
keeping the hem smooth (not puckered) as you go.