Making the cold frame is so easy!
One bale at each end and one on each side of the feed sacks, as illustrated. Overlap the bales slightly at the corners.
I want my cold frame facing south (just as solar panel installers do). So on the north side of the cold frame, place the last two bales on top of the bottom one. Stagger them so they meet in the middle of the bottom bale. The two outside corners will stick out beyond the bottom bale, but the main part of each upper bale will still be adequately supported.
Sow seeds or plant transplants. (I put in the sturdiest beet, broccoli, brussels sprouts and arugula seedlings that I thinned from my main beds. If they don't take, I'll sow some arugula. If they get too tall, I'll add another level of straw bales.)
Place windows at an angle between the high bales and the low one.
When rain is predicted, I'll uncover the cold frame to reduce the need for watering. Our nights aren't that chilly yet, but I'm going to leave it in place for now as an experiment. This is my first time to use a cold frame, and I want to see how it does.