On the surface it makes sense that hugelkulture would provide many benefits including: increased microbial activity, low maintenance, decreased water requirements, increased planting surface area, nutrient release from rotting wood, turns a waste product into an asset and increased soil temperatures from some composting action.
However, we wanted to test it and be able to see those positive results for ourselves.
Essentially it is taking course woody debris and fine organic matter and covering it with soil. This creates a raised bed with a microclimate that can be used to suit different plants in close proximity. In a nutshell, that is hugelkulture (mound - culture). The bed can be relatively small and low to the ground or hugel beds can carry on for thousands of yards and be six feet tall or even higher. Sepp Holzer is probably best known for utilizing hugelkulture and the technique is well known in the permaculture world but is not exclusive to that movement.
Several points were mentioned above but let me expand on a couple of points.
One of the main benefits promoted with hugel mounds is water retention in the woody material that provides moisture for plants during periods of drought. Depending on climate and the site this could result in no need for irrigation or at the very least reduced irrigation. Have you ever walked through a forest and kicked an old rotted out log? It might not have rained for weeks yet digging into that rotted material and you find moisture. Rotted wood soaks up water like a sponge. That is what will happen inside of a hugel mound.
Another important help is that over time and depending on the condition of the wood when the bed was built will begin to decompose and give off heat. This can aid in germination of seeds and potentially prevent plant loss during a late or early frost. With that decomposition comes nutrient release and a reduction or elimination of other fertilizers. The increased microbial activity hastens the whole process building soil fertility.
It doesn’t have to be complicated. It can be done below ground as in digging a trench filling it with woody debris and covering with soil or lay woody debris down on the ground and cover with soil. It depends on your climate, the site and your preferences. There is no fixed rule on how high, wide or long to build them. Let the creativity flow! Start with the largest logs and lay those down first, layer up with smaller material. If you have excess material like leaves, manure straw or any other excess organic matter you can add that as well. Fill in the gaps and crevices with soil and top the whole thing with 1-2’ of soil. Build to your liking and design.
If you are going to plant right away, then you will want to use “seasoned” wood. Wood that is partially decomposed already. If you are prepping the bed to be used several months from now then it would be fine to use newer wood. Preferably use a mix of cured and green wood of different sizes. Stay away from trees containing jugulone like black walnut and hickory. Also, if you have the opportunity steer clear of highly rot resistant wood like cedar and black locust. However, I wouldn’t hesitate to use some of that wood if it was well worn. Basically use what you have on site that is appropriate. Here, in North Idaho, we use predominantly birch, as well as fir and pine. For the fir and pine we only use well-seasoned wood to ensure the tannin levels are already lowered.
We decided to put a hugelkulture bed in our food forest to test all of the purported benefits of the technique. We decided to keep if very simple by building a smallish bed that is about 10’ long, 7’ wide and around 4’ high. It has settled to about 3.5’ high. It was very important to us to test the moisture retention aspect of this bed. Therefore, we decided that we will not add any water. Whatever we get in rain is what the bed gets. In our climate, we get a decent amount of rain (avg 28” annually) but most people irrigate their gardens around here to keep them growing during the dry months. With that we build our hugel mound with mostly rotting birch of varying sizes. We also added some fir and pine into the mix. We planted a few items: cabbage, onions, beans, lavender, and mustard as kind of control plants to see what happens. We put the lavender on top and the other plants near the base. With the rest of it we seed bombed it. We took whatever seeds we had left over, soaked them and tossed them on the pile. Here is a partial list of the seeds we used: calendula, clover, beans, peas, squash, amaranth, lupine, and peppers to name a few.
As of the time of this writing we have not watered the mound in 17 days. In that time, it has rained here a decent amount so the true test will come later in the season. However, I will say that we have had very good germination from seed and the other plants are doing very well. This might not sound earth shattering to many people but what would happen if we planted all those seeds in trays and put them outside with no regular water? Likely a whole lot of attrition. We have also taken some soil temperature readings. Again, nothing mindblowing but we did get about a 5-degree warmer reading from the hugel mound than the soil next to the hugel mound. The numbers will likely improve more and more over the next couple of seasons.
So far we are enjoying the experiment and it will be fun to see what produces, what bolts and what dies! Time will tell and we will be documenting along the way. Check out our online community for great content! Sean and Monica are available for consulting work regarding property analysis & design, and speaking engagements.
Sean and Monica Mitzel are the proprieters of Huckleberry Mountain Homestead & Breakfast a Bed & Breakfast with a homestead twist. They homestead with their family on 40 acres and are using permaculture techniques and methods for the property. The homestead is a demonstration and education site where they teach workshops and raise dairy goats, sheep, pigs, rabbits, chickens, and ducks. The Mitzels have planted food forests, guilds and enjoy wildcrafting and propagating plants. Sean and Monica can often be found speaking and teaching at different events. To learn more about the Mitzels, visit The Prepared Homestead. Read all of their MOTHER EARTH NEWS posts here.
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