At 8 feet high and 13 feet across, the galvanized-steel wire and cedar structure here provides 60 square feet of extra growing space. Carpenter Shawn Ogle explains how he built it.
1. To create the curved top, wet two lengths of 1x8 cedar, lay them across sawhorses, and hang a 10-pound bag of sand from the middle of each board. Keep wetting the wood over the course of a couple days until it bows.
2. Prepare to pour four footings by setting one of the curved boards on the ground and using paint to mark the locations of four equally spaced 4x4 posts along its back side. Excavate 30 to 36 inches below grade for the footings, using the markings on the curved board as a guide. Fill each with 4 inches of gravel, set a 4x4 pressure-treated post inside—turning it to make full contact with the curved board—then backfill the hole with gravel and soil.
3. Screw the curved boards to the post tops. Conceal fasteners along the front side with a strip of 1x3 cedar trim.
4. To build the wire panels, sandwich 5-by-4-foot sections of galvanized-steel wire between 1x3 cedar, screwing through the front of the frame into the back.
5. Clad all four sides of the posts by screwing on 1x4 cedar; then screw the framed trellis sections to the posts. Set birdhouse finials on top of the posts, as desired.