Hugelkultur is the practice of growing on a mound. The mound is made up of woody organic matter with a layer of soil. The purpose of growing on the mound is to create more favorable growing conditions for plants.
This topic allows me to go deep in terms of understanding techniques, knowing that its usage is available to almost everyone. This ancient practice is often associated with Permaculture, it has almost become a symbol for it, in certain parts of the world.
For clarity, “hugel” means “mound” in German, so we can trace its usage back to the Northern ethnic communities in Europe; essentially, these people were working with nature, to create better growing conditions for their culture(s).
And hugelkultur can be a very valuable practice and can be implemented at several scales, it is important to understand the design thinking behind it, in order to assess whether it makes sense to use it in your situation. In recent history, it has become used in more and more places, thanks to the pioneering work of Sepp Holzer, in mountainous Austria.
What needs to be taken into consideration is that wood was Sepp Holzer’s most convenient natural resource, at such high altitudes. Although other options could apply (boulders, rocks, gravel for example), the resources needed for cutting and placing wood and logs in strategic positions are minimal, by comparison.
The work of creating and using hugelkultur is pretty straightforward (all types of woody material, placed under soil), but the ecological functions that they perform rely on understanding and thoughtful action.
Stop, spread and soak water in the soil.
This function is very similar to that of swales, but the contexts are quite different. Swales are tree growing systems that are suited for slopes up to 18-20% and align on contour. Hugelkultur, on the other hand, is a technique used on difficult and steep terrain; most of the time, precision instruments or machines can’t be used, so the mounds aren’t always even in size, or spread.
But by putting together these mounds, water is retained for much longer in the soil, thus encouraging the decomposition of wood by fungi; so a secondary function is soil creation, and that makes the task of growing annual vegetables slightly easier. It’s important to be aware that in Sepp Holzer’s case, the growing season is extremely short: 90-100 days on average.
By using a widespread resource (wood), he improves the conditions for the intensive systems (gardens) considerably.
Speed up succession
This is another basic function that we can encourage, as stewards of the land. If we’re staying within a framework similar to that of Sepp Holzer, using wood that is not very valuable (but abundant), in order to create improved conditions for the more valuable crops (food, forage, fruit trees, etc) makes perfect sense.
With slopes in mountainous regions up to 35%, or even more, valuable crops have almost no chance to grow unless the soil is deep(er) and can retain more water. The growing season being so short, conditions have to be almost perfect for crops to reach maturity (in the case of annuals), or to be established by the time the conditions worsen again (in the case of fruit trees).
By returning Carbon to the soil, and letting it decompose in favorable conditions, the succession can happen even without human-intensive systems.
For reasons that are slightly different, hugelkultur can also work in contrasting conditions such as in deserts. This is where land is flatter, and the sun is so strong and close to vertical; thus, hugelkultur can be used to create microclimates (for shade and water retention) that allow to grow more varied plants.
Encourage the development of fungi in the soil
The health of entire ecosystems depends on the spread of fungi, and their symbiosis with bacteria, lichens and other life forms. By returning woody material to the soil, especially where it’s needed because of the shallow depth, this technique slowly creates new pathways for the mycelial network to grow and spread. This process is slow, and sometimes the goal it helps reach is forgotten; but at high altitudes, these webs of life help slow the flow of energy and nutrients, and create much better conditions for life to thrive at lower altitudes.
So hugelkultur is more than just a one-dimensional technique, in has an impact in the long term as well. When used appropriately (meaning where the resources are abundant, and where succession is done with / for more valuable elements), its benefits are numerous.
Where woody resources are scarce, or where the buried logs are completely covered and the soil becomes anaerobic, it makes little sense to try hugelkultur. Other alternatives exist, and should be taken into consideration, for performing as many of the functions already mentioned.
About the role of fungi in the soil, from the Soil Food Web School: https://youtu.be/Q-utjOt6YcI
Create micro-niches for more varied growth
It is quite obvious, by this point, that hugelkultur creates microniches that greatly improve the quality of soil, and even the surfaces available for plantation. When creating a mound, we arrive at a triangle shaped feature, where the two sides can be used for planting, instead of just the base.
More so, each side and each level (high, mid and low) offers different growing conditions. That ranges from well-drained to damp soil, and from sunny to shady. Depending on orientation and prevailing wind, mounds can also protect from phenomenon such as drying of the soil, or light saturation.
As we’ve seen that hugelkultur is viable in different climate types, for each situation it adds a different variable; where in Sepp Holzer’s case the mound slows water, but the top is better drained than the normal condition, in the desert the mound represents a hub for moisture retention. The wood can actually help bring humidity towards the surface, by capillarity, where it would normally stay below the ground, because of the sandy soil.
Read more about Guild layers and Functions: https://vinepermaculture.com/guild-layers-and-functions/
Invite bio-diversity and enhance aesthetics
This function too is linked to the others mentioned above. In difficult conditions, depending on variable criteria (high winds, high evaporation, high altitude), a hugelkultur mound is a contrasting shape; by inviting interactions with wildlife (for example, attracting insects seeking shade, or protection from the wind), as well as capturing organic materials and seeds carried by the wind, the mound creates the conditions for more plants to thrive.
In conclusion, this is a technique that can perform a lot of beneficial functions, and hopefully this article has shed some light on the reasons you might choose to use it, and what you can expect from it as you advance on your Permaculture journey.