The word HugelKultur refers to a special form of a no- or low maintenance gardening where you use logs and other woody material to create a small hill that will slowly release nutrients to your plants and at the same time this system is capable of storing water, almost eliminating any need for watering of your plants.
Hugelkultur is a non-dig system that requires little maintenance over a long period of time, sometimes decades, depending on the size and quality of the system. The hugelkultur is in short a pile of logs, twigs, leaves and green compost intermixed, topped with soil, on which finally a mulch is spread. The woody parts of the hugelkultur will slowly decay over time, releasing nurtrients, and act as a water reservoir because the rotting wood content acts like a sponge. The system therefore doesn’t need external fertilization and no, or very limited watering. Most of the maintenance consists of filling holes made by animals and replenishing the mulch layer.
Before you start building a hugelkultur you should collect enough materials to get started. You do not have to finish in one go, but there should be some basic materials available. The most important material is wood in the form of branches and logs. Logs that are partially already rotten are preferred over fresh logs. If you use fresh logs it will take some time before all the functions of the hugelkultur are working at an acceptable level. Smaller branches and twigs and leafy material can also be used in large amounts. Some green component such as fresh leaves or grassclippings are also welcome.
A hugelkultur is started by digging a hole into the ground for the entire length of the bed. This excavation should be 30-50cm deep. Put the excavated soil to the side. It can be used later for the top soil of the hugelkultur by removing any existing weeds and their root systems. The hole can now be filled up with you large logs. Gaps in between the logs can be filled with twigs and branches or other brown material. The ideal is to make a layered approach. In between and on top you can now add a layer of green material if available. On top of this go now your smaller logs and branches, filling any holes with other brown or green material. The idea is to stack the logs with intermediate green layers till you reach a height of at least 60 cm. The green material will accelerate the composting process in the first year. Later fungi and other microbial processes will start decomposing the wood slowly releasing nutrients for multiple years and creating a spongelike structure that retains water with high efficiency often making it unnecessary to water plants on your hugelkultur.
It is now possible to top of your log-hill with clean soil or compost. On top of this a thick layer of mulch is applied. For the mulch grass clippings, straw, a wood mulch, or a similarly suitable material can be used.
Basically your hugelkultur acts like a slow-decomposing compost heap with an unique microclimate. The soil layer on top acts as a foundation where your seedlings can be planted. Their roots will quickly spread into the inside and extract nutrients and water. The mulch on top prevents weeds from establishing.
The hugelkultur requires therefore a large effort to build but subsequent maintenance is much lower than in other intensive gardening methods. There is no or hardly any need to add nutrients to the system. Water management is mostly done by the hugelkultur itself although be aware that it takes a while for the wood to start decomposing. New beds can therefore require more watering. Weed management is made easier due to the thick mulch layer on top. It virtually eliminates the need for regular weeding. The fact that it is literally a hill makes the hugelkultur a raised bed. Your plants are often easier to reach, check, maintain and harvest.
Long Term maintenance of the hugelkultur consists mostly of re-applying the mulch layer when needed and filling holes created by animals and the weather. The hugelkultur will gradually get lower over time due to the decomposition of the woody materials inside it. This is normal.