I've been square-foot gardening for over a decade now and just wanted to say kudos to Gardener's Supply for a good product. I purchased two of their 3' x 3' "Grow Beds"--essentially a 10" tall plastic lumber raised bed.

They arrived via UPS and it took my husband about 5 minutes to assemble each. They're a little more pricey than untreated pine (they run $35 each), but we've got more projects than we can possibly do around here, so the time savings is worth it for us.

Even if you're building out of wood, I heartily recommend the 3' x 3' size box. It's an easy reach to the center from every edge. I'm a very lean and limber woman, and I still had trouble squatting and reaching to the center of the 4' wide boxes to do detailed work.

Yippee!