Hugelkultur 101: Benefits, Variations, Bed Construction

Hugelkultur is a form of permaculture gardening that has been getting a lot of attention in recent years.

The name means “hill culture” or “hill mound,” and the practice originated in Germany.

Hugelkultur is a no-till, sustainable gardening method where logs and organic material are used to create free-form raised beds.

What is the hugelkultur gardening method? Hugelkultur beds are created by layering a base of large logs with branches and sticks, organic materials, and finally topsoil. The main principle is that over time, the logs and organic material will break down, releasing nutrients into the surrounding soil and improving water retention. 

What if I told you you never had to water your garden again? Hugelkultur beds can hold all the water they need (except for extreme drought conditions).

This makes hugelkultur one of the most eco-friendly and sustainable gardening methods.

By not using water and fertilizer, hugelkultur saves resources while creating delicious and nutritious foods. 

Hugelkultur: The Basics

Hugelkultur can be adapted to fit any size garden and can even be done in containers.

By layering logs and branches with organic material, you are adding everything the soil needs to support a bountiful garden. 

The process of decomposition begins in smaller organic materials.

This layer is made up of anything and everything you would include in a compost pile – food scraps, grass cuttings, manure, straw, eggshells, coffee grounds, shredded cardboard, wood chips, etc.

Beneficial microbes will proliferate while decomposing the organic material, creating the perfect environment for the wood to be slowly broken down. 

Since the wood and organic material provide nutrients to the soil and hold plenty of water, the hugelkultur bed is very low maintenance once it is established.

This process also sequesters carbon in the soil, which is important in the fight against global warming.

An additional benefit to hugelkultur is that the decomposition process generates heat, warming the bed and elongating the growing season in cooler climates. 

Benefits of Hugelkultur 

Hugelkultur has several benefits and almost no downfalls once the beds are established. Creating the beds is truly the hardest part. 

The logs at the base of the mound hold in water exceptionally well. This reduces or eliminates the need to water the garden.

The branches and twigs increase aeration in the soil and add nutrients to the soil as they break down.

Not only is this method a sustainable way to produce nutritious food, but it is a carbon-negative operation, meaning you are sequestering more carbon than you are putting out. 

Variations of Hugelkultur Gardening

Hugelkultur beds can be created in many ways. This lists the most common variations, but many gardeners create beds that are a combination of techniques. 

Freestanding

This is the most common and straightforward variation of hugelkultur.

Your mound can be started anywhere by piling the logs, branches, and organic material directly onto the ground. There are no supports or structures to hold up the raised bed. 

Enclosed

This is a combination between a traditional raised bed and a hugelkultur bed. A structure, usually made of wood or sheet metal, is created to contain the bottom of the mound.

The logs and branches fill up the structure with organic material and topsoil is mounded on top.

This adds some stability to the base of the mound and can make the garden look more attractive. 

One type of enclosed hugelkultur bed used wood pallets as the support structures on the side of the mound.

This allows the gardener to support the mound while still planting between the slits of the pallets. 

Underground

An underground hugelkultur bed begins by digging a trench where the mound will be placed.

The depth depends on your preference, but the deeper the trench, the more logs and branches can be placed inside. Layer the bed as usual.

All the dirt removed from the trench can be used as the topsoil for the mound.

Since the bottom of the mound is underground, this hugelkultur bed might not be as tall as a freestanding or enclosed bed. The height is up to your preference.

Some people do not mound their bed up at all, and the top is flush with the ground. 

Do You Have To Dig a Trench for Hugelkultur?

No, you do not need to dig a trench to construct a hugelkultur bed.

However, it gives you more space to include logs and organic material, which increases the water retention and amount of nutrients in the mound. 

Hugelkultur Bed Orientation

For traditional vegetable and fruit gardening, the hugelkultur bed should be constructed north to south (length-wise).

This allows the entire bed to receive fairly even sunlight as the sun moves from east to west throughout the day.

You can also plant fruit trees or bushes along the side of your bed to act as a windbreak (if necessary for your location). 

What Kind of Wood To Use With Hugelkultur

There are a few kinds of wood to avoid using in your hugelkultur bed, but a majority of types of wood are fine to use.

Softwoods will break down easier than hardwoods, meaning the mound may not last as long.

Rotted wood that is a couple of years old is the best option for your bed because the decomposition process has already started.

The next best option is deadwood. There is nothing wrong with using fresh-cut wood, it just might take longer for the decomposition process to be in full swing. 

Some of the best options for wood are alder, apple, cottonwood, poplar, dry willow, and birch.

How To Layer a Hugelkultur Raised Bed 

Beginning from the ground up, layer your materials as follows: logs, branches and twigs, compost materials, topsoil.

Depending on what compost materials you have available, this portion can be multiple layers. For example, use a layer of old sod, a layer of food scraps, a layer of wood chips, etc.

How Many Hugelkultur Layers Do I Need?

The basic structure has four layers – logs, branches, organic material, and topsoil.

However, if you are building a taller mound or have plenty of organic materials to include, there can be several layers of organic materials. 

Graphic showing the layers needed for hugelkultur gardening.

How Deep Should Hugelkultur Be?

If you choose to build an underground hugelkultur bed, you should dig a trench at least 2-4 feet deep.

For an underground/freestanding hugelkultur bed (which is a recommended combination), you should dig a 1-foot deep trench.

The deeper your trench, the more wood it can hold, and therefore, more nutrients are added to the soil and more water can be retained.

How Tall Should Hugelkultur Be?

Permaculture experts recommend hugelkultur beds 6-7 feet tall. This is because the decomposition process will cause the mound to slowly shrink over time.

Additionally, a taller mound provides more surface area for planting.

However, your hugelkultur bed can be any height that you desire.

For those living in communities with homeowner’s associations, a shorter mound may go unnoticed by the neighborhood watch.

You can always add more compost each year to slowly grow the height of the mound. 

What To Plant in a Hugelkultur Bed

What you plant in your hugelkultur bed will depend on the location/orientation of the bed and the amount of sunshine it receives.

In general, the top of the mound is the best location for plants that need less water but enjoy more sunlight. The bottom of the mound is better for heavy drinkers that are shade tolerant. 

Almost any plant will thrive when grown in a hugelkultur bed. The only consideration is to avoid heavy nitrogen feeders during the first year.

Fresh wood utilizes a lot of nitrogen when the decomposition process begins, depleting the surrounding soil of this necessary nutrient.

To offset the wood’s use of nitrogen, you can plant nitrogen-fixing plants, such as legumes, during the first year. 

Getting Started: How To Construct a Hugelkultur Bed

A trench filled with split logs in preparation for a hugelkultur bed.

These are the directions to construct a combination underground/freestanding hugelkultur bed. Adjust accordingly if you are using a different variation. 

1. Dig a Trench

Remove existing sod from the desired location of your bed. Keep the sod and any soil removed, which can be added to the mound later.

Dig a trench that is 1 foot deep and as wide as you’d like (3-4 feet wide is recommended). 

2. Fill the Trench With Logs

Loosely place your cut logs throughout the trench. Depending on the size and depth of your trench, you can place the logs horizontally or vertically. You may also have multiple layers of logs.

3. Add Branches to the Pile

Once all your logs are in place, begin piling smaller branches and twigs on the pile. This will help create the final shape of the mound and add support. 

4. Layer Organic Materials

If you have sod from digging your trench, place it grass side down on the branches.

You can then place all of your organic materials – food scraps, grass cuttings, shredded cardboard, wood chips, manure – onto the mound. This can be done altogether or in separate layers. 

5. Build Mound to Desired Shape

Use your organic materials to shape the mound as high and wide as you’d like. A steep pile will give you more surface area on which to plant. 

6. Cover With Topsoil

If you have soil remaining from digging a trench, you can add it onto the pile as the outer layer of topsoil. This can also be done with compost. 

7. Let the Bed Rest or Begin Planting

At this point, the bed is ready to use. However, many gardeners prefer to let the bed rest for a couple of months before planting. This allows the mound to settle and the decomposition process to begin.

Beneficial microbes and creatures will have time to move in, helping to create a thriving, nutrient-rich environment. 

Wood To Avoid in Hugelkultur

Certain woods should be avoided because they are extremely slow to break down, contain toxins, prevent seed germination, or can root from branches

  • Black walnut
  • Cedar
  • Black locust
  • Willow
  • Acacia
  • Cypress
  • Redwood
  • Sequoia
  • Black cherry 

Is Spruce Good for Hugelkultur?

Spruce is most likely okay for your hugelkultur bed, but it is not preferred because of the tannins and sap in the wood.

It would be best to use a mixture of different woods if you’d like to use up spruce logs.

Is Pine Okay for Hugelkultur?

Like spruce, pinewood has tannins and sap, which is not ideal. In addition, it is slow to break down and can inhibit beneficial microbes.

If you would like to utilize pine logs, include them in a mixture of better woods.

Is Birch Good for Hugelkultur?

Yes, birch is an ideal wood for hugelkultur beds.

What Can You Not Put in a Hugelkultur Bed?

  • Dog or cat waste
  • Treated grass or plant cuttings
  • Weeds that have gone to seed
  • Treated wood
  • Inorganic materials 

Does Hugelkultur Attract Termites?

The logs utilized in a hugelkultur bed will not attract termites any more than fallen logs in a forest or on your property.

If you live in an area where termites are found, there is always a possibility that they will find any wood. 

If you are concerned about termites, place your hugelkultur mounds a good distance from your home.

For natural pest management, birds and chickens enjoy eating termites. 

Does Hugelkultur Tie Up Nitrogen?

If you use fresh cut logs when you build your hugelkultur bed, the logs can tie up nitrogen during the first year.

This is due to fungi breaking down the wood as part of the decomposition process.

If you have lots of organic material and manure on top of the logs, it may not affect the nitrogen of the soil.

Using older wood that is rotten or has started decomposing already will not affect the nitrogen levels of the soil. 

To prevent losing plants to low nitrogen levels during the first year, you can add nitrogen back to the soil through some different methods:

  • Plant nitrogen-fixing plants, like legumes.
  • Add coffee grounds to your mound.
  • Include plenty of manure when constructing your mound.

Can You Plant Trees in Hugelkultur?

It is not recommended to plant trees directly on a hugelkultur bed. Since the bed is raised above the ground, it is not stable and the tree could easily fall over.

In addition, the branches and logs create large air pockets which are not ideal for stabilizing roots.

However, if you plant your trees along the side of your bed, they can still receive the benefit of the added nutrients and retained water in the soil. 

Does Hugelkultur Work in Containers?

Yes, hugelkultur can be scaled to any size, large or small. In a container, create the same layers as a freestanding mound. 

How Long Does Hugelkultur Last?

A hugelkultur mound can last for over 20 years. With proper care, the bed retains the nutrients and water-retention abilities for years and years. 

Common Hugelkultur Mistakes To Avoid

With this gardening method, there’s plenty of room for creativity and customization; however, there are a few practicing that should be avoided in order to get the most out of your new beds.

Not Covering the Wood Entirely

It is important to cover the logs and branches with an ample amount of organic material and topsoil.

Not enough coverage will mean the plants don’t have enough soil to put down healthy roots. In addition, exposed wood will evaporate precious moisture out of the mound.

Not Building Tall Enough

As the logs and branches begin to decompose, the organic material and topsoil will begin to settle into the air pockets.

This can cause the height of the bed to shrink by 1-2 feet within the first few months. 

Choosing the Wrong Variation

An underground hugelkultur bed is recommended for dry, hot climates because the decomposing wood has better protection and insulation to retain water.

Humid areas with plenty of rainfall will not need the extra protection, so beds can be freestanding. 

Conclusion 

Now that you know the ins and outs of hugelkultur gardening, you can effectively implement these techniques in your garden.

Not only can hugelkultur save you time and resources while producing a delicious and bountiful harvest, but your garden will be helping sequester carbon and leave the earth healthier than you found it.