Then I began putting in 3 foot metal fence posts about every five feet. The posts were five or six inches from the edge of the chicken wire.
These posts have a 3-4 inch stabilizer that needs to be pounded into the ground and so it was necessary to cut away some of the wire around where the post was going to go so that the stabilizer didn't "hang up" on the wire as it was pounded in. I found it useful to take a two foot piece of rebar and pound it in where I wanted the post to go to make sure that I wasn't going to encounter shale. If the rebar went down as far as the post needed to go I knew it was okay to pound in the post. I used a level to make sure each post was as vertical as possible.
The next step was to add the four foot vertical chicken wire, attached to the posts. Four foot fencing on three foot posts was intentional. Groundhogs are good climbers. But they don't like wobbly fences. The top foot of the chicken wire is not connected to anything and it tends to flop backwards toward the path. It is secured to the post near the top with zip ties so that it can't easily be pulled off the post by a ten pound ball of climbing fur.
The next step was to crawl around the fence and connect with vertical chicken wire to the horizontal chicken wire with zip ties every six to nine inches so that the fencing effectively becomes one piece. The final step was to pull soil and mulch over the chicken wire on the ground so that the wire was covered.
There is only one entrance to the three garden beds that are enclosed in the fencing. It is where the black pot is in the photo. I slid a piece of plexiglass on the inside of the fencing using rebar to keep it close to the two fence posts and I slid an old bike route metal sign (gathered some years ago from Onondaga Creek during a clean-up) on the outside, again using rebar to keep it close to the other side of the two fence posts. Presumably ground hogs cannot climb up either of these surfaces.
The only potential weakness I see is that around the opening and at the corners the fencing is taut and could be climbed. At the top the animal would then have to jump into the garden. I plan to add a few aluminum pie plates in these areas because apparently things that move frighten ground hogs.