This shows the two big beds outside the potager fence, and the T-frames installed in the one bed.
This bed is 5 feet wide so the top of the frame extends a foot on each side. As you can see, he placed 3/4" conduit on the edges between the frames instead of the traditional 2x4's. He thought these would tend to sag less over time. If you were going to make this into a high tunnel or greenhouse sometime later by installing hoops at the top with the pvc, then you would need to use boards. Next year I am only going to place the hoops at the bottom for a low tunnel for an earlier start on the tomatoes.