The idea is build a bed over a load of old tree stumps and branches. Over time all the wood breaks down into soil – pretty simple stuff.
As luck would have it we had plenty of spare wood around the yard so one afternoon (some months ago) we picked it all up and dumped it in one place.
At first we weren’t quite sure what to do with it, but we have started by growing alfalfa on some soil thrown in various places.
Since we have to wait about 10 years for the wood to decompose this project could take a while 🙂