I have a 20' x 16' raised bed that's made out of treated lumber that I had left over from another project. It's comprised of a 4" x 6" base with a 4" x 4" top run to hold it all together square. I have very sandy soil; so I amend each year with compost, manure, etc. I hand turn the soil to a depth of 10" or so; like to get out and work up a little sweat in the spring (and drink some beers after). Seems to work O.K. for me. Just another "yankee's" 2 cents. Peace.