It sounds Germanic and it is. Hügelkultur, Heugelkultur, hügelkultur is growing things in Hügelbeets (“mound beds”) and they have a long tradition in Germany.
Raised beds then.
Yes, but they’re raised beds with a difference.
The base of the bed is a thick layer of wood in various stages of decomposition. Largest pieces go to the bottom, followed by smaller lengths, clippings, brush, bark, etc, then straw, hay, leaves, followed by the upturned sod or topsoil removed to create the bed. The idea is that the wood as it decomposes not only constitutes a source of organic material and fertility for the bed, mimicking what happens on the forest floor, but acts as a giant sponge, holding a large reservoir of winter rainfall and releasing it to plants as they grow through dry summers, reducing the need for irrigation. A deep enough layer of wood may be sufficient to hold enough water for the entire summer.
I came across the term yesterday while thinking about how I was going to manage the irrigation of our new raised vegetable beds, so it was this last part that really got my attention. This system seems purpose-designed for the Portuguese climate of winter rains/summer drought.
I found a couple of videos on YouTube (one above) and then all 9 pages on the subject on the US Permaculture forums. Then yet more convincing photographic evidence in this blog post, and ending up with Sepp Holzer’s acres of enormous Hügelbeets high in the Austrian Alps.
This had to be a much better way of constructing our raised beds than simply adding large amounts of compost and mulch to the surface, and a much better use for old timber than burning it, so today I started on the process of turning the biggest bed so far cleared and marked out into a Hügelbeet.
I started on the highest and driest part of the bed and, after putting in boundary boards, dug it out to a depth of around 2 feet. The soil on this terrace is a beautiful fine clay loam and the thick matt of nettles we cleared last year attests to its basic fertility, but it’s severely lacking in organic material and life. This is what we aim to restore as soon as we can.
We don’t have any big blocks of wood available onsite to use, and certainly nothing as massive as was used in this video, so it’s unlikely we’ll achieve a self-sufficient bed as far as irrigation is concerned. But what we have is enough to make an attempt from which to gauge how much wood we would need to use to hold enough water for healthy growth through an average Portuguese summer. Fortunately, the vast majority of the rotting chestnut timbers from the old roof are still onsite, so we can use a mixture of woods in different stages of decomposition, rather than exclusively maritime pine (which is what we have most of here and which is quite acidic).
Another feature of Hügelbeets is that while the composting process is continuing, the heat it produces warms the soil covering the bed, making it possible to extend the growing season. We’re perhaps being a touch optimistic in planting lettuce seedlings in it in January, but nothing ventured …
Hügelkultur in Mediterranean Climate – Portugal (Tamera)