Squash leaves cascade out of this hugelkultur compost garden box. Wood stumps and branches form the deepest layers which are covered with leaves, grasses, and fresh kitchen compost. Newspaper separates the compost from the topsoil.
This is a great time to plan and build a new garden bed.
Gardening in Cook County can be challenging because of the cooling effect of Lake Superior. A friend who lives on the shore told me, “It’s like growing things inside a refrigerator.”
Our boreal forest soils can be difficult too: bedrock, clay, gravel, and sandy silt. These elements are important for good soil structure, but need organic material to create a good harvest.
How can you add organic material to your garden soil, create more heat and retain moisture?
One solution is to create a compost garden, a layered garden that allows you to grow herbs, vegetables, and fruits while the compost is breaking down and generating heat in deep layers below the plant growth. Hugelkultur, sometimes called lasagna gardens, are layered compost gardens.
The word hugelkultur means hill culture or hill mound. The original idea was to re-create the forest floor. The layers of decaying wood and brush support and nurture the new plants and trees. People began digging trenches on their land, filling those trenches with small stumps of wood and covering those stumps with leafy branches and brush. On top of that moisture-rich wood and branch base, they would layer grasses, leaves, ash, and vegetable compost. The final layer was several inches of some kind of topsoil to support the seeds until their roots could reach into the deeper nutrient rich layers.
I started a compost garden in a raised bed about five years ago. My wooden garden box is eight feet long and three feet wide. The walls of the box are two feet high. The garden box is built from old deck wood. On my property, I had wooden stumps (some partially rotted), branches from birch, elder, apple, and poplar trees, leaves, grass, pine needles and vegetable compost to layer. Ash and newspaper have been used to separate the topsoil from the deeper compost layers.
Each year the bottom layers settle more as they break down. There are probably still some wooden stumps in the lowest layer of my garden box. The wood takes the longest to break down and as it decays, provides storage space for water and air in the deepest layers of the garden.
Plants that have to grow into the soil (like carrots, radishes, onions, and beets) have not done well with my shallow topsoil. Their roots don’t tolerate the harsh environment of the fresh compost. Plants that thrive in my garden are squash, cucumbers, and snap peas. These are plants that develop vine-like supports and grow their vegetables above the soil.
Each hugelkultur garden will be different because of the materials that are used to create the mound. If you are able to provide deeper topsoil, you will be able to grow the root vegetables and even potatoes. It is a bit of work to set up the garden at first because you have to gather and organize your compost materials. But once the garden is established, annual maintenance is simple.
I remove the available topsoil and set it aside. Then I refresh the garden with layers of needles, grass and leaves, and fresh vegetable compost. I cover those layers with some ash and newspaper and replace the topsoil. Then it is time to plant again, time to grow again.
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