What is Hugelkultur? The Ultimate Raised Bed

Take raised beds to the next level with hügelkultur

January 8, 2021
Hugelkulture
Paul Wheaton RichSoil.com

What is hugelkultur, anyway? When I first heard the word, I thought it must be a new kind of yogurt, but no—it is a raised garden bed. “Hügelbeds” can be translated as “mound culture”—in which plants or crops are grown on raised beds with a mounded shape and form. Many swear that it takes raised beds to the next level. Find out why.

What Are Hugelkultur Beds?

Hügelkultur (HEW-gul-kul-TOOr) has been used for centuries in eastern Europe and Germany, often as part of a broader permaculture system.

Put simply, hugelkultur is a centuries-old, traditional way of building a garden bed from rotten wood and plant debris.  These mound shapes are created by marking out an area for a raised bed, clearing the land, and then heaping up woody material (ideally partially rotted) topped with compost and soil.

Downed trees, fallen branches headed for the brush pile, and rough lumber can all be used; you are essentially taking rotting wood and allowing it to compost in place for a superfertile, moisture-retaining garden bed.

These mounds can be 5 to 6 feet high—massive heaps of logs, branches, leaves, straw, cardboard, grass clippings, and manure or compost mounded to be wider at the bottom than at the top. As the wood shrinks and breaks down, a hügelbed sinks; one that is 6 feet high, for example, will ultimately sink to about 2 feet. 

How to Build a Hugelkultur Bed

  1. First, select a sunny spot that’s roughly 8x4 feet. (A bed built parallel to a slope is a good idea, as it will catch water.)
  2. If there is grass or the site is weedy, you’ll need to clear it down to bare soil. Just mow and cover the area with cardboard or wood chips to suppress growth.

  3. Now dig out shallow pits, retaining the turf or topsoil for the top of your mounds. Make the pit or trench 12 to 18 inches deep, keeping the same depth the full length of the bed. Beds need to be narrow enough that you can reach to the center; we’d suggest no more than 4 feet across. 

  4. Next, lay the woody material into the dug-out area, starting with large logs or downed trees. Add a layer of branches and twigs. A mix of hard and softwoods is recommended. Avoid using woods that are slow to rot such as locust, cedar, or redwood or any that release toxins that inhibit plant growth such as black walnut.

  5. Like building a lasagna garden on top of wood, top it with grass and grass clippings—nearly any kind of organic material—and pack firmly. If you have excavated turf, place it root side up on the wood.
     
  6. Continue to arrange the wood longitudinally and as tightly as possible. The pile can be as long and high as you like but I suggest a 2- to 3-foot high bed as it’s easier to work with (and can last without water for two or three weeks). Some folks build them really tall, up to 5 or 6 feet high but I would need heavy equipment to achieve that.
     
  7. Then, water the layers well. “When it sprouts mushrooms, you know it’s wet,” says Tim Murphy, a gardener in Kingston, New York. Fill in any cracks or spaces with grass, leaf litter, and manure. “The tighter the better,” he adds.
     
  8. Finally, top off the bed with 2 to 3 inches of topsoil and a layer of mulch. 

If you build this in the fall, let the whole thing settle over the winter and it will be ready for planting next spring.

In the first year, the pile will need watering as the wood breaks down. The rotting wood will also be using up nitrogen that would otherwise be going to your plants so it is recommended that you plant legumes the first year since they produce their own nitrogen.

Note that the greater the mass, the greater the water retention. Experienced hügel gardeners have found that if the beds are high enough, they don’t require irrigation at all after the second year. Steep beds also mean more surface area for planting; plus, their height makes harvesting easier.

Eventually the rotting wood will hold water like a sponge, making the bed drought-resistant. The top of the bed will be naturally drier than the base so you can plant things that need more water nearer the bottom and those that like it drier near the top. You can plant in the sides as well as top and bottom increasing yields in a small garden.

A Living Sponge

In the first few years, the heat-producing composting process warms the soil in a hügelbed, providing a somewhat longer growing season. The decaying woody matter is a source of long-term, slow-release nutrients and helps to keep excess nutrients from filtering into groundwater.

The wood, acting like a sponge, stores rainwater to release during drier times. Hügelbed soil is self-tilling over time. As woody material breaks down, tiny air pockets open in the crumbling soil, allowing air to reach plant roots. In time, you can plant into the topmost layer of soil/compost, which becomes rich with beneficial microorganisms.

First-year hügelbeds can be big producers. Murphy reports a harvest of 120 pounds of cucumbers and 42 good-size pumpkins, as well as giant sunflowers, from two first-year beds. Murphy looks beyond the first few years, though: “These are serious, permanent raised beds. What you’re building is a living, breathing sponge.” 

The Benefits of Hugelkultur

The rotting wood hosts beneficial fungi, bacteria, insects, worms, and microbial growth that create nutrients your plants can use. Over time the mound will shrink as the wood rots but you can always add more soil or compost to the top. You will have created an ecosystem in which the beneficial organisms will thrive.

Hugelkultur is popular with gardeners who have struggled with heavy clay and poor or compacted soil. It is a good way to build up a planting bed and turn woody debris into a garden.

More Hügel Hints

  • The best woody species for hügelbeds are alder, apple, cottonwood, maple, oak, poplar, dry willow, and birch.
  • Avoid any treated wood, cedar, and allelopathic or toxic species, such as black cherry and black walnut.
  • Super-rotten wood is better than slightly aged wood.
  • Plants that grow especially well in hügelbeds are cucumbers, legumes, melons, potatoes, and squashes.

See more articles on Raised Garden Beds.

About This Blog

Get inspired by Robin Sweetser’s backyard gardening tips and tricks. Robin has been a contributor to The Old Farmer’s Almanac and the All-Seasons Garden Guide for many years. She and her partner Tom have a small greenhouse business and also sell plants, cut flowers, and vegetables at their local Farmer’s Market.

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