I decided to use 2x12x10ft. boards. They were about $8 apiece. I also bought a 4x4 inch post which was also around $8.00. The Square Foot Gardener says that you only need to use 6 inches of soil, so you could use 1x6's. Also, using 10x10 is going to cost me about $100 to have filled with a soil compost mix from a local materials outfit. You figure 27 square feet in a square yard of soil, and since I don't want to fill it to the top, and I'm going to amend the soil some, I need 2 yards. All together this garden is going to cost me around $200.00. However, it will be moveable if I need to, and it's very large. That's a ton of vegetables, and over the years....what's that word? Amortize?
You will need 16 bolts, like this, 3/8x6,
and washers and nuts to tighten them up.
I realized that if I set the boards up on the posts with some space underneath like a real bed, we could easily dig holes under the posts to get the top level, which is what we did. We cut the 4x4in. posts to 18 inch lengths, giving ourselves a 6 inch leg to use when leveling. If your space is not as sloped as mine was, you could leave less space on the "legs".
I made two templates with drill marks spaced so the bolts wouldn't hit each other.
Now for the dirt, the peat moss, and the vermiculite. Hmmmm. Seeds or plants?