The boxes are 4 feet by 8 feet and are made of untreated wood. Instead of making the posts flush with the box he made them either 2′ or 3′ high so that he could more easily attach chicken wire around the boxes. The chicken wire doubles as support for my tomatoes and cucumbers.
My husband used 2 1/2 inch 3/8″ lag bolts with 1 1/2 inch fender washers. He panned out the holes so that he could get more of a bite into the posts. He said that would not be necessary if he had used 3 inch lag bolts, but we had the shorter lag bolts left over from building a horse shelter.