Why Your Garden Needs a Hugelkultur Bed (and How to Make One)
Garden beds require several components: compost-rich soil, full of nutrients and good drainage; soil warm enough for seeds to germinate; and moisture to keep plant roots hydrated. Gardeners will spend countless resources creating these conditions through watering, composting, fertilizing and tilling, but you can create these conditions without outside work by building a hügelkultur.
What is hügelkultur?
The German concept of hügelkultur is a mound of organic materials that are composted inside. The way you lay down the organic material is critical to the success of the bed as it ensures the most efficient composting. Large materials such as logs occupy the bottom of the mound, layering on smaller and smaller materials as they pile up, ending with soil on top. Oklahoma State has some beautiful illustrations that help visualize how laying works. The tops of these mounds are ideal for planting, and over time the beds become more successful. As the middle of the mound breaks down organically, it creates compost-rich soil full of microorganisms, worms and mycorrhizae (beneficial fungi). Composting creates heat as the material breaks down (if you’ve ever seen a compost pile smoking, that’s decomposition). The humus-rich soil retains moisture but has amazing drainage thanks to the tiny tunnels created by worms and fungi.
Bed materials hügelkultur
A hügelkultur flowerbed is like starting a fire in reverse: you start with larger pieces and then fill the space with smaller and smaller material. Smaller material composts fastest, “igniting” larger pieces. You will need logs, either long or round, for the bottom of the pile. Then branches, and then scrub, wood chips and topsoil.
Since this is usually when people are pruning trees, it’s a good time to get some free logs. If you pay attention, you’ll notice neighbors trimming their trees or the city doing proactive work ahead of winter storms. You can always stop and ask for these magazines, and they are the hardest to find; everything else is easy.
One note about harvesting logs: avoid these types of trees: anything allelopathic (they produce toxins that inhibit the growth of plants around them), such as black walnut; anything that grows from cut green branches, such as willow; something aggressive like the Tree of Heaven; and finally, anything that is rot-resistant, such as cedar.
Designing your hügelkultur
Your bed can be any length, but the longer you make it, the more material, including large logs, you will need. Their height isn’t necessary—they need to fit the space—and your beds don’t have to be straight, either. Since you’re building from scratch, you can fill the space with a serpentine bed or design a circular bed around a core piece. It’s helpful to plan your bed by running garden hoses through the space according to the shape of the bed to see how they fit.
You’re unlikely to assemble your bed in a day: hügelkultur is a process, so while you can set aside materials to start with, you don’t have to commit to the final project in advance. You can adjust as needed to suit the space and materials. Once the initial layer is created, you can re-evaluate and determine what materials you will need along the way so you can collect them.
How to collect hügelkultur
You always start your bed by laying down the logs. They should have the same rough shape that you want the bed to have and be as close to each other as possible. You always try to have as little empty space between them as possible. Remember that the bed will become wider than the log due to the material laid on top.
Next, you will layer the branches, starting with the thickest and ending with the thinnest. Place them on top of the logs and also tuck them into the spaces left by the logs, trimming them as needed. The goal, as before, is to fill as much space as possible. In this part, you will likely find that you need to collect more material or specific material as you fill in gaps and find that you need smaller or larger branches. Again, it’s helpful to think of it as fire.
The next layer is the scrub, and it can take different forms. For example, you can use all the biomass from your summer garden – all the vegetable and flower plants that you intended to compost. Grass clippings and manure are good materials for this layer. The smallest trimmings from autumn harvesting will do; you can also use wood chips. The idea at this stage is to fill in any remaining spaces and create a layer on top of the branches and logs. This type of garden waste is flexible and can be placed anywhere. Any biomass destined for compost, as long as it is not infected with disease, is a good candidate for a hügelkultur bed.
The last layer is topsoil, and since it is the finest material in the mixture, it should fill any remaining spaces and create a mound shape. There are no nutrients in the top layer of soil; it’s a blank canvas. You can use compost or a three-part mixture from the nursery, which will make a good planting medium, but the point of hügelkultur is to create this material yourself – it just takes a while to get the bed going. . Topsoil is easy to obtain; someone is always giving something away on Craigslist or similar sites, and chances are you have it in your yard.
Once you’ve assembled the entire bed, you’ll need a layer of mulch on top. You can use leaves and straw. or more wood chips. Cover the bed with a good layer of mulch and then water the entire bed to begin the composting process.
Planting in a hügelkultur garden bed
A good reason to build a bed now is to get it “ready” for the winter; by spring it will be ready to receive plants. When it’s time to plant, you’ll push back the mulch so your plants’ roots have access to the soil underneath, then plant as usual. You will not need additional materials such as fertilizers, even if you usually use them when planting. When moving the mulch back, leave space around each plant so that the mulch does not touch the plant.
At this point, treat the bed as you would any other. It may need water occasionally, but should hold moisture better than regular raised beds. Over time, the bed will become more productive and efficient as the interior is heated and the bed is composted.
Hügelkultur beds are an important part of creating permaculture in your garden, where all waste is returned to the garden, forming a loop.