It is a German idea, as you might have guessed, and seems to be a sort of raised bed. But it is formed of a mound over rotting wood. Googling it produces mostly permacuture avocates, but adding a touch of credance maybe is this article by Alys Fowler in the Guardian.
Why am I interested, when normally I don't favour raised beds ? At the bottom of my allotment, my last bed is underperforming. It gets very wet down there, and the soil isn' t great. The light could be better but for an overhanging silver birch. My thought is that this is an ideal spot for a raised bed of some sort; I have a fair amount of already partially rotted pear wood, the good stuff being destined for the stove, and a small collection of stumps etc. The overhanging birch tree might be persuaded to fall in too
![Wink :wink:](./images/smilies/icon_wink.gif)
My main cause for doubt is that decaying wood might be expected to deplete nitrogen. Adding the grass sods should help, but also I could grow leguminous crops/green manure, and/or water it with high nitrogen liquid (No, not that one, I was thinking of nettle juice).
Anyone have any thoughts ?