The installation of a hugelkultur is a very simple yet highly effective way of constructing a raised garden bed. Hügel is a German word that translates into mound, which makes sense as the basic idea is to pile up wood and branches to a steep mound, cover it with soil, and immediately plant it. The logs and branches will make lots of air pockets for your plant’s roots to extend to, retain water that is released to the roots as needed, and release nitrogen and other nutrients to the plants as they decompose. If your hugelkultur is 1.5 meters high or taller it will retain enough moisture that your plants can survive without watering for 3 whole months (once they are big enough for their roots to extend to the wood, of course)! Hugel beds are a great way to boost your veggies using leftover logs, branches, and clippings. As a bonus you are storing CO2 in the soil at the same time and harvesting is made easy as you don’t need to bend down as far.
Step 1 – preparing the ground
Select a suitable location: somewhere with space to easily access your hugelkultur from all sides and preferably not too far away from the logs and branches you will use. If you are planning to set up your hugel bed on a slope it is absolutely essential not to construct it parallel but divergent to your slope! Once you have decided on a location, loosen the soil in the area in which you want to construct your hugel bed. If you dig down 20cm or so and pile up the soil up on the side you will already have some soil ready to cover your mound later.
Step 2 – piling up logs, branches, and clippings
Pile up your logs, branches, and clippings into a steep and between 1 and 1.5m tall mound. Steepness is crucial here as the wood otherwise won’t have enough ventilation to decompose properly! According to permaculture guru Sepp Holz you should aim for at least 45 degrees of slope, although he recommends going for 60 to 70 degrees. While you are adding to your mound you can already feed your wood with some water to kickstart the decomposition process.
Step 3 – adding the soil
Once you’ve got all your wood piled up neatly, add the soil layer on top. Piling on the sod (the bit of soil that has grass growing in it) upside down first will make things a lot easier as your soil won’t fall through the branches. Once again: make the mound as steep as possible! I usually slap the soil onto the sides so it doesn’t fall down.
Cover your entire Hügel with a soil layer of least 20cm. In the above image we also covered the fresh soil with a sheet of plastic to protect it from the tropical sun as long as the cover crops are still germinating. If you are constructing a hugelkultur in an area with heavy rainfall it is advisable to dig a diversion drain all around (with an outlet at its lowest point), so that excess water can flow off. In drier areas you will want to conserve all moisture in your mound, so you don’t need a drain.
Step 4 – start growing
Once your Hügel is neatly covered with soil you can start growing immediately. Cover cropping is usually a good idea (try clover, a great nitrogen fixer) to quickly protect your soil from erosion. Alternatively you can also just heavily mulch your new hugelkultur with grass clippings or the like. Then just plant all your veggies between the cover crop, which you can chop and drop for mulch every once in a while. Keeping a constant ground cover in the form of crop plants or living mulches like clover is the best way to maintain moisture in the soil!
You can really plant any type of vegetable into a hugelkultur, from lettuce and cabbage, tomatoes and zucchini, to potatoes and carrots – all will benefit from the nutrients released by the decomposing material!