Rather than cutting out an inset on the bench, I crocheted a bench "cushion," and here are the steps I took to make that cushion:
1. Make 2 rectangular frames out of 19-gauge wire, which will be the base and opening of the cushion.
2. Crochet enough rows of double-crochet stitches to create a swatch that fits inside one of the frames, like so:
3. Double crochet around the entire swatch. Each of the side posts per row will require 2 double-crochet stitches; close the round with a slip stitch.
7: Fill with dirt and your choice of plants. Water thoroughly.