If you’re building a backyard structure like a pergola or an arbor, you’ll want to elevate those post ends above grade to keep water from getting to them. Now you could just let the cardboard form stick up out of the ground and set the post on that like everybody else does, but there’s a better way.
Dan Jensen, of Tigard, Oregon was building an arbor in his backyard and he realized that he could make a decorative top for the concrete piers using a plastic plant container turned upside down. First, install your cardboard forms so they’re flush to grade. Next, you’ve got to cut the bottom out of the plant container—I use a utility knife. With the bottom cut out of the plant container, you simply center it over the concrete form, nestle it into place, and you’re ready for concrete. If you find the form riding up a little bit on the concrete, just push it back down and put a concrete block on top until it sets up.
