I wanted to build a raised garden bed this year and decided that I had enough materials around the homestead to build one. My goal was to build it with little or no cost using reclaimed materials. I found a spot near my greenhouse that I was also building at the time that looked to be pretty level.
Step 1: first things first
I wasn't sure how big I wanted to make this, but knowing that I only had a few cement blocks to work with, I decided to go somewhere around 7 or 8 feet. I put a stick in the ground and tied a piece of bailing twine to it and cut off a length that looked about 8 feet. I then placed a block at the end of the string about every three feet until I had a perfect circle. I rearranged the blocks to get them to line up and then eye-balled the keyhole part to where it not only looked right, but big enough to be able to work in there.