If you’ve never heard of “Hugelkultur” (German for Hill Culture) don’t feel bad. I had never heard of it either, but I knew I wanted to try it last year. Hugelkultur is actually surprisingly simple. It recreates the natural forest floor by layering decaying matter, wood, twigs, and leaves and all covered by dirt to form a mound, hence the name “Hill Culture”. It isn’t pretty, but it is surprisingly effective and fertile.
Hugelkultur does a few other agriculturally effective jobs in an urban garden. It creates deep compost. It holds water just beneath the surface of the soil. It attracts worms, microbes, and other insects because of the constant supply of nutrients and moisture available. Finally, it drastically improves the soil structure of a garden. See my blog on compost and soil composition, here. It has one major draw back though: Hugelkultur is a lot of work! And I mean a lot of work.
The first step of building a Hugelkultur garden is building a trench to replicate the deep compost of a forest floor. Two 18″ deep trenches, five feet wide, and 12 feet long. If you’re curious, that’s 90 square feet of soil. Once you have a sufficient trench, you need to locate the proper wood to set into the trench. When we bought the two lots that comprise Mezzacello in 2013 we had to cut down nine silver maples that were at the fence line and had been tortured by our local electrical provider. Maple is deciduous which was appropriate, as pine is far too acidic to work well in a Hugelkultur mound. We chopped the trunks and major limbs into 12″ sections and stored them in the back service yard after we had cut the trees down (waste not, want not). We hauled out the trunk and branch sections and brought them to the trenches. We placed the logs and larger trunk pieces into the trenches. Then we placed extra logs and branches around the spaces between the trunk pieces. Around all of this we layered in twigs and smaller branches. We filled in the remaining space with leaves and straw. We covered all of this with several cubic yards of soil. These were our initial hills.
Over the course of 18 months (six seasons), the hills flattened and the soil became extremely rich. We planted the mounds that first spring with hairy vetch so the roots could extend down into the Hugelkultur and further decay the wood. The Hugelkultur mounds are very rich, and really do hold a lot of moisture. Probe testing the moisture and Ph levels indicate high levels of moisture and a consistent level of 6.5 for Ph. During those 18 months the only real issue we had with the maturing Hugelkultur mounds was an infestation of Belladonna. It was probably growing as a vine on the trees, and when it took root, it spread like wildfire in the rich environment. You’ll want to keep an eye on this if you try this process.
I’m interested to see how the hill will support life and growth this spring now that it has had 6 seasons to mature. I am not sure what I will plant in there, but I do know that I won’t need to water whatever grows there as the Hugelkultur mounds do hold a lot of water – similar to a swale. Maybe that will be where I plant my peas and beans? They pull a lot of nitrogen out of the environment and deposit it into the ground. We’ll see what this growing season holds in store!