A hügelkultur is a horticulture technique for building a garden bed using mounds of buried logs. Using alternating layers of organic, nitrogen-heavy materials with layers of dead, carbon-heavy materials, this style of garden bed acts as a compost and slowly decomposes the buried, rotting wood underneath. The decaying wood decays into usable carbon for plant growth (recall that all living things are made of carbon) and is vital to the soil food web, feeding earthworms, fungi, bacteria, etc. These critters then digest the organic material to build fertile soil. More earthworms means healthier soil!
Benefits of a Hügelkultur
- The decomposition of material creates heat as a compost to raise the soil temperature and insulate plants,
- The logs wick water and store it as a reservoir,
- The larger material allows air to penetrate the soil and plant roots,
- The rotting wood stimulates mycelium,
- And, save money on potting soil, while getting rid of wood.
Observation of Natural Forests
Hügelkultur is German for “mound culture.” Initially, growing on top of wood in this way to promote healthy soil and decompose wood was from an observation. If you notice while hiking in woodlands, you see the forest floor is exactly this: dead wood from trees that had collapsed, fallen branches, and twigs which could help as either nitrogen or carbon in the mix. This collection, along with creeping vegetation and forest decomposers like fungi and insects, created a very fertile area. You may also notice that gardeners do not have to put work to fertilize natural woodlands! The practice could have been used for hundreds of years in Eastern Europe, although the phrase was officially coined by Herrman Andrä in 1962.
How: Compost on Dead Wood
The layers of a hügelkultur are shown below. The main concept is to just bury logs or sticks – so that is the first layer (1). Afteer that we add a “green” high-nitrogen layer (e.g. partially-decomposed manure, coffee grounds, etc.), a “brown” high-carbon layer (e.g. dead leaves, paper, charcoal, etc.), and more “green” (e.g. green leaves, kitchen scraps, etc.)(2). You want to make sure that it alternates so that the nutrients and decomposition work between the layers to efficiently break down material over time. A layer of soil and / or mulch (3) goes on top of that. We use native soil, but you can use fancy soil. And here is where the patience comes in: ground cover (4). Typically, you put ground cover in in the fall during the first rains and chop it down to amend the soil in the spring. If you use material in this process that is mostly decomposed already, then you could directly plant your veggies and shrubs. However, if your manure is fresh or you have material that needs to break down, the ground cover will act as a sacrificial layer to break down any harmful bacteria that could be in the fresh manure (e.g. E. coli) and convert manure into available nitrogen for the production plants to be grown. Finally, plant your babies! I suggest perennial veggies and shrubs for garden beds (5) to carbon farm and put less work into. Enjoy your thriving (6) hügelkultur garden bed 🙂