What Is Hügelkultur?

The new hügelkultur mound on the South Whidbey Tilth campus.

Hügelkultur is from the German words hügel (mound) and kultur (culture) and can be translated as mound bed. You build a mound bed starting with larger logs and branches, then layering on smaller woody material, compost and soil. You plant directly into the sides of the mound.

Why build a mound bed? The short answer is that you thereby build healthy soil. Rotting wood hosts all kinds of microbes, insects and worms that break down the woody material slowly, creating nutrients for plants. Soil high in organic matter retains water. Using downed trees and yard waste to build the ultimate raised bed is a great alternative to burn piles or hauling to the dump. Especially if you are struggling with poor soil in your garden, mound beds can help you turn yard waste into nutrient-rich, moisture-retaining soil.

In the first year, a mound bed needs some extra care. When wood is first composting, it may not put enough nutrients back into the soil, so it is best to plant legumes that create their own nitrogen. You may need to water. But after the composting gets going, the mound will provide plenty of nutrients and retain water like a sponge. As the wood rots, the mound shrinks. You can add more soil and compost to the top to keep your mound bed producing year after year.

Mounds typically cover an area three feet by six feet and are three feet high, built like a pyramid to create steep sides. Mounds don’t need to be high, but the higher the bed, the more water it retains and the more planting area you create. And, you will not have to bend so far to weed.

One of the best wood species for hügelkultur is red alder, which is plentiful here on Whidbey Island. Other good picks are apple, cottonwood, maple and oak. You want to avoid treated wood, cedar, black cherry and black walnut because these woods contain toxins that prevent other plants from growing.

What you plant will depend on your situation, but some great food plants for a mound are vines and sprawling plants like cucumbers, legumes, melons, potatoes and squashes.