Here is my superadobe raised garden bed. I used a natural plaster of sand, pure clay and cattails. I built it completely by myself; it was fairly easy.

The great thing about this garden bed vs. other ones I've seen out of wood is that no chemical preservatives are leaching into the soil. Another advantage is you can sit on it. Also, it will last many more years than a wood frame.

I filled the bottom half with rocks, then a landscaping cloth, then the top soil. The plants are growing like crazy; it sure works well. What is interesting is how the rocks imbedded in the mixture make the plaster even stronger. I also experimented with a little bit of wheat paste in my re-do after the water resided (see below). Each section of the garden bed is an experiment. The section that is doing the best in rain and freezing temperatures is the section with the imbedded rocks, which I sealed with flour paste, I also added the paste to the mix. After the rocks were imbedded, I waited about an hour until the plaster hardened up a bit then put a layer of flour paste on the plaster around the rocks, it did an amazing job to seal it up.

This garden bed was an experiment, it was built on a shore line of a large lake. I wanted to see how earthbags and plaster held up to water. What I didn't expect was the lake levels rising higher than ever before. I also didn't expect such large waves; the garden bed was battered for countless days. The plaster held up well when submerged in water, but it was unable to hold up to the constant barrage of large waves. Luckily the garden bed drains very well, most of the plants recovered. I was impressed with the strength and affordability of this earthbag structure. The cost to build this was appox $80.