The concept of a permaculture garden is to provide long-term solutions that maximize outputs and minimize inputs, while cycling energy and resources through the system.
This creates closed-loop efficiency within your system and prevents excess waste. In fact, one of permaculture’s most favored sayings is ‘there’s no such thing as waste, just things in the wrong place’.
Hugelkultur is a great example of recycling resources on your site to create long-term fertility in the soil. In doing this, you create beds that become more productive over time, helping to produce better quality crops with higher yields.
But what is Hugelkultur and why should you be implementing it in your permaculture garden this spring?
What is Hugelkultur?
Hugelkultur literally translates from German as ‘Hill culture’. In short, it refers to mound-style garden beds that are higher than regular raised beds. The bottom layer of these beds is filled with buried logs as a source of long-term nutrients to the plants.
In fact, one of the most important characteristics a hügelkultur bed should have, is that the bottom contains decaying wood debris and other compostable biomass so that, as it breaks down, it improves soil fertility, water retention, and warm the soil.
Hügelkultur is not necessarily a new technique, but it hasn’t been around that long, either. The term was first used in 1962 by a German gardener named Herrman Andra. He touted the method as a way to use up woody debris without burning it as well as to build soil fertility.
When we’re building our permaculture gardens, especially in late winter and early Spring, we often find we have logs, branches, and sticks in abundance from pruning our fruit trees.
Rather than leaving these resources to go to waste, Hugelkultur makes excellent use of these carbon-rich sources of nutrients.
The logs are buried at the bottom of the beds which then slowly decompose over time. This creates humus (decomposed organic matter) at the bottom of the beds.
The thing about wood is that it contains lignans – these are carbon fiber compounds that help to build the structure in the wood. These are slow to decompose giving a far more stable humus, as well as breaking down over a much longer period of time.
As permaculture designers, we aim to provide solutions not only in space but also in time – this is one that lets us set it and forget it, knowing our plants will get a healthy source of food for a long period.
In fact, Hugelkultur beds can provide nutrients for several years, whereas compost and mulch on the topsoil needs to be constantly replaced.
The Benefits of Hugelkultur
The advantages of hugelkultur spread over many years. Not only does Hugelkultur retain water and provide long-standing nutrients, it also helps reduce waste on your site and cycle energies.
The humus that is created begins feeding the plants directly from underneath. This encourages roots to reach down and anchor further into the soil, mirrored by larger growth above the ground.
This helps grow stronger, healthier crops that produce a more fruitful, higher-quality yield.
What’s more, the spongy composition of the humus on the lower levels also helps to retain water. It can absorb water and hold it for far longer periods of time, and at lower levels.
This reduces the chance of the water being evaporated by the sun and allows access to stored water in drier seasons.
Again, it also encourages the roots to reach down further and support the plant’s strength and growth. In addition, hugelkultur beds tend to act like sponges in that they are well-aerated. The logs and branches hold water but as they break down, the soil becomes more porous. No more tilling!
Many permaculture gardeners that use this technique say that they do not need to ever water their Hugelkultur beds after the first year (unless in very arid climates).
The breakdown process, where the logs turn to humus, produces heat. The heat keeps the soil warm, protecting against frost in the colder months. This extra heat contributes to faster crop growth and more bountiful yields. You will also be able to grow a bit longer in the season.
Wood, in particular, decays quite slowly. Because it is more gradual, it can provide long-term nutrients on a more consistent basis.
While some gardeners claim that you need to rebuild your beds every five to six years (and that’s true, in many cases), if you are using large bits of wood, you might have available nutrients for several decades! It could be even longer if you use hardwoods.
Hugelkultur is a no-dig method of gardening, which means that aside from being far less effort, it also doesn’t disturb the complex ecosystems that form within the soil.
Even when we make compost and put it on our topsoil, the act of moving the compost will disturb these intricate universes – often letting in large amounts of oxygen that burn up the nutrients – which then have to start rebuilding again when laid on the soil. Hugelkultur prevents this from happening as it stays under your beds for years without disturbance.
Hugelkultur helps to recycle nutrients and energies through your site in a productive and eco-friendly way. Often we end up burning excess branches and twigs that are pruned from trees.
While this can produce ash (which is good for the garden and ash beetles) it also releases carbon back into the air. By using hugelkultur beds, you’re sequestering the carbon the trees sucked out of the air during their lifetime.
The mound-like structure of the bed also provides you with more planting space than flat beds or small raised beds.
As you only have to do this process once every few years, this really reduces your labor and materials inputs while providing you with more and longer outputs through years of crop cycles.
How to Build Hugelkultur Beds
It’s relatively simple to build Hugelkultur beds. These beds allow for a range of flexibility when it comes to the materials you can use, which is important as the best nutrient providers for your soil tend to come from the local environment in which the beds will be built.
In this sense, try to look for logs and branches from your own site with which to build.
What Type of Wood Should I use for HugelKultur?
While you can use any trees for Hugelkultur, hardwoods break down more slowly (which is why they’re used for furniture!) and will provide nutrients over a longer period.
|Tree Types You Can Use||Tree Types To Avoid|
|✓ apple||╳ cedar|
|✓ alder||╳ black cherry|
|✓ acacia||╳ California pepper tree|
|✓ oak||╳ Siberian Elm|
|✓ poplar||╳ black walnut|
|✓ maple||╳ camphor wood|
|╳ black locust|
You’re looking to use tree types such as apple, alder, maple, oak, poplar, and acacia. Make sure everything is fully dead so it doesn’t start sprouting under the soil.
You can get a head start by introducing a few logs from softer woods that break down faster, which will allow you to gain nutrients in the short term, too.
My personal recommendation is to use a combination of fresh and rotten wood.
The rotten wood walls support the plants earlier on, as it will already have a jumpstart on breaking down, and it will also “inoculate” the soil with beneficial microorganisms and fungi.
Fresh wood will be in it for the long haul, helping to support your plants over time.
These softer woods, along with smaller twigs and branches should be added at the top of the log pile to give the new plants nutrients as they begin growing. Equally, you will want a mixture of tree types as this will ensure that you have varied nutrients within the soil.
Some people use multiple layers of wood to build their hügelkultur beds, selecting large pieces for the bottom layer and medium pieces for the one above that.
You can even add a third layer with even smaller wood pieces. The larger the wood on the bottom is, the better the bed will be when it comes to retaining water and supporting the health of your plants.
Just keep in mind that the larger the logs you use, the larger your bed will be. If you use large logs that are a foot across, your bed will need to be about three feet tall or larger.
Tree Types to Avoid in Hugelkultur
There are some tree types that should not be used when building hugelkultur beds. This is because certain species of tree contain toxins and are allelopathic – meaning they inhibit the growth of other plants.
For example, most permaculturists know never to plant apples next to walnuts, because the walnuts inhibit the apple tree’s growth – the same principle applies to Hugelkultur beds.
Equally, some trees like firs and pines release tannins into the soil. These can turn the soil very acidic, as well as leach into water supplies.
Trees to avoid include camphor wood, black locust, eucalyptus, black walnut, Siberian Elm, California pepper tree, black cherry, and pretty much all cedar varieties.
You can use fir and pine if it has been aged, but try to break it down into smaller parts first, and layer it close to the top with a good mix of other woods.
What Else Do I Need?
You will need some form of mulch to go on top of your log layer. Just like sheet mulching, you want to use the lasagne layering pattern to layer green and brown material on top.
You can use anything from leaves to grass clippings to kitchen waste for your green layer, while straw, hay, dried leaves, and corn husks make a great brown layer. Wood chips also work well.
Remember to make sure you have mixed materials for the mulch to provide a range of nutrients. If you need more instructions on mulching, you can get them here.
You will also need pre-made compost. You can buy it from gardening stores (make sure it is organic), but it is usually best to use your own as it will consist of plants from your native environment and works toward recycling energies back.
Building Hugelkultur Beds
Choose a Location
Firstly, you need to locate your beds. When building any kind of garden beds, we try to build on contour – meaning that we build the bed parallel with the lay of the land.
Imagine a map with red lines that indicate steepness – you want to build along those lines. This keeps the beds level and stops water from running down slopes you may create by going against the contours.
If you’re building your hügelkultur bed on sloped terrain, the beds need to be built so that they are at an angle to the hillside instead of running parallel. This will ensure that the beds receive even amounts of water. Try to position them so that the beds are against the prevailing wind direction.
Secondly, you need to consider the sun’s aspect. If you are creating tall beds one next to the other, you want the sun to travel across the length of the bed. Otherwise, plants on the north side will get far less sunshine.
If this is unavoidable, you need to consider plant selection, with more shade-loving plants on the north side of the mound. However, planting the beds from east to west will give you better sun throughout the day.
Time to Dig
Next, after measuring your bed out, you want to start digging to make a trough to lay your logs into. Dig around 30-60 cm (10-20 inches) into the ground.
The width is entirely at your discretion, however structurally, the wider the bed is, the taller you’ll be able to build it, creating more surface area.
It is important to remember though, that the bed will widen out further than the trough you have dug, as you’ll be building material on top.
Generally, gardeners tend to dig the trough about a foot to a foot and a half wide. This will create a bed that is 2-3 feet wide in the end. Any larger than this and you’ll struggle to reach the crops at the center of the bed.
When fully built, the base should be 2-3 times wider than the top of the mound and the height should be about the same as the width.
Remember, though, that if you create a bed that’s 3 feet tall, and the plants grow another 3-4 feet tall, you may have trouble reaching the fruits and vegetables. Some people incorporate logs to stand on at the edge of their beds, or a border that’s raised to help them reach.
The steeper you build your beds, though, the better. A steep hügelkultur bed will resist compaction from increased pressure. It will also give you more surface area to grow your plants and it will make it easier for you to harvest. Not only that, but a steep bed will hold water better.
You can have some fun as you design your beds, too! Feel free to build them in circles, swales, or even mazes.
Place the Logs
Place your logs into the hole. You want to get as much wood as you can in, without packing it too tightly. Make sure you mix up the wood types to give varied soil.
Try to leave some small gaps between the larger pieces of wood so that some soil can fall between them later. Keep the width of the bed a bit smaller than what you ultimately want it to be.
You can pile the logs up slightly higher than the trough to help define the pyramid shape that the bed will eventually work out to be.
Smaller branches, twigs, and softwoods should be at the top, with your bigger tree trunks, branches, and hardwoods at the bottom.
On top of this layer, you want to add mulch. Interestingly, some people place turf upside down here. It helps to hold the structure, and the green material sparks the decomposition process of carbon by introducing nitrogen.
While this is a good idea, you shouldn’t go out and buy turf; but this can be a useful way to recycle resources if you’re removing an old lawn or have some laying about.
Layer your mulch on top to about the same height as the wood – 60cm (23in) at the lowest, but the more mulch you put, the more compost will build below the surface, providing super healthy soil and a rich and complex ecosystem.
Make sure your mulch (especially the brown layers) is moist as this will get the decomposition process underway immediately.
Another helpful tip is to try and fill in the gaps around the logs with the mulch (and later, with your compost, too). This will help things settle better so you don’t lose mass later on.
You will also have fewer issues with rodents and your bed will have better water retention. You won’t have to worry about your plants’ roots running into air pockets later, either.
On top of your mulch, you need a layer of compost. Spread it liberally on top, but you won’t need more than 10-20cm (4-8cm) of compost, as the whole process will be making more underneath.
Now you need to cover the whole lot in the soil you removed from the trough. The soil will provide an insulative layer, like a clay oven; absorbing thermal mass and getting the process started.
If you don’t have enough compost to fill the bed, there are other things you can add at this time, too. Some options include manure or other nitrogen-rich material.
I’d recommend avoiding hot manure from animals like chickens, as it might contain too much nitrogen if you’re planting in the first year. If you mix it in with something else, though, it would be fine.
The soil also stops weed seeds from finding their way into the super-nutrient compost and taking over.
Consider Additional Layers
If you want to keep adding on to your hügelkultur bed, you can add additional layers. Consider adding a next layer of medium-sized wood, followed by more mulch and compost. The more layers, the better, as it will help your bed stay fertile and functional over time. Just follow the same steps listed above.
Before you plant, I also recommend adding one more layer of mulch. Hügelkultur beds are excellent when it comes to retaining water and fighting weeds, but they can still dry out – or attract weed seeds!
Adding an extra layer of mulch will help jumpstart your beds and make your beds virtually maintenance-free as you move forward in the growing season. This top mulch layer should be about two inches thick.
Planting in a Hügelkultur Bed
You can plant in your bed immediately. Just dig into the soil, pull back the other layers, and plant seeds and seedlings straight in. I have done this with quite a bit of success.
However, some gardeners recommend waiting to plant. You can leave the beds for several months and return to find them just as fertile and ready to go as they are when you left.
The only disadvantage to planting right away is that the beds will settle a bit as things start to break down. As they decompose, you’ll lose a bit of mass and may need to add more soil or compost, which can be cumbersome if you’ve already planted.
As an alternative to this, just build your beds a bit higher than you think you might need them to ultimately be.
You can grow anything you’d like in a hugelkultur bed. It’s important to note, though, that the bed will decompose relatively quickly (unless you use lots of bulky materials, like tree trunks) and will, as a result, lose fertility after the first year or so.
Because of this, you may want to plant nutrient-needy plants like tomatoes and pumpkins the first year, while later, you can grow less needy crops like peas, beans, and strawberries.
Other plants to consider growing in your first year include squashes, corn, potatoes, cucumbers, celery, and cabbage.
In most cases, a hugelkultur bed will last around five or six years. After that, you’ll have lost enough mass and fertility that you should rebuild it.
As with any gardening idea, there are some potential challenges and drawbacks associated with building and using a hugelkultur bed.
First and foremost, you are going to have some labor involved with building your bed. That’s true of building any kind of raised bed, but this kind of method is particularly labor-intensive because you’re going to have to move all kinds of resources to the bed, like logs, grass clippings, compost, manure, etc.
However, the upside is that once you get your beds built, there’s very little else that you have to do. It’s kind of a one-and-down sort of situation with minimal interventions needed on your part later on.
Size of the Beds
Hugelkultur can be inconvenient if you are building large beds. This is kind of a double-edged sword, since the larger your beds are, the better they will be at retaining water and providing all of the other benefits we mentioned above.
There are benefits to this, again, but it can be challenging to build and maintain a bed that large.
You will also have to be careful about the type of wood you use. Black walnut is a natural herbicide, while materials like oak and pine contain tannins that can sour your bed. Other wood, like cedar, takes a long time to decompose – this can hinder the ultimate efficacy of your bed.
You can get around this by researching the best wood types to use and by using wood that is partially decomposed. Wood that is well-rotted will have lost most of its tannins and will break down more quickly.
Again, you’ll also want to avoid using treated lumber of any kind so that you don’t introduce harmful chemicals to your garden bed.
This is a less talked about issue as it relates to hügelkultur, but still worthy of mention. Nitrogen drawdown is when logs, which contain lots of carbon, require lots of nitrogen to decompose.
During the first few years of growing your hügelkultur bed, the decomposing logs might steal nitrogen from the soil, robbing plants that might need it.
To get around this, again, using semi-rotted wood can help. It will have already taken on some nitrogen so you don’t have to worry about it robbing quite as much from the soil. You can also add plenty of nitrogen-rich material to the bed (like manure for grass clippings) for seed deposition.
Another option is to plant nitrogen-fixing crops in the first year. This is contradictory to what I told you before, about planting these crops later, but if you know you can’t add nitrogen-rich material when you build your bed, it’s a good way to get around it. Consider Planting crops like beans and peas to fight this nitrogen deficiency if it’s a particular concern.
Pests and Rodents
Another issue that many gardeners note when building their hugelkultur beds is their ability to attract rodents and other pests.
This can be most easily avoided by limiting the amount of open space inside the bed. Pack the holes full of soil and compost or they will become nesting spots for rats, mice, squirrels, and other pests.
Another tip? Lay out some piles of rocks near the hugelkultur beds. This will create a snake habitat.
Although you might not be terribly fond of snakes, they’ll control the population of rodents as well as slugs and other pests, too. You can also allow chickens to run through the beds, but they may decimate your crop populations!
Variations on Hügelkultur
If a traditional hugelkultur bed doesn’t appeal to you for whatever reason, there are some variations you can apply to this method.
One is to build a hugelkultur bed out of slash piles. If you have a ton of woody debris to use up (whether from pruning trees or cutting a chunk of property), you can build a hugelkultur bed atop the pile without moving it.
Keep in mind that it will settle over time, and it can produce issues with rodents, but it requires little labor and will provide you with an option of disposing of the slash without having to burn it.
You can also use a formal raised bed as a starting point for your hügelkultur bed. It will look a lot nicer, as it won’t be a trench dug into the ground, so you can easily incorporate it as part of your landscape.
However, you will have to pay more money to build the raised bed frame and you may have some issues with the “hot” hugelkultur causing the wooden sides of your raised bed to decompose, too (if you use wood sides).
A final option is a hugelkultur bed that is fully buried. A buried bed will be out of sight and out of mind, meaning it may look more like the traditional garden bed.
However, you may find the size to be a limiting factor here. In order to build a substantial bed, you’re going to need to dig a very large hole – one that will require many hours of backbreaking labor or the use of an excavator.
However, once it’s built, you’ll have a highly fertile plot.
The only other disadvantage to this method is that the planting surface will be at ground level, eliminating one of the most oft-touted benefits of hügelkultur- its accessibility when it comes to maintaining the garden!
You may also have to mulch more heavily to keep out weeds, since the bed will be at ground level and therefore more privy to invasion from weed seeds.
For most people, the traditional hügelkultur method will be best – but consider some of these variations if you want to get more creative!
At a glance…
Hugelkultur is one of the most effective ways to cycle back nutrients into the soil. Not only does it provide rich and complex soil for your plants to grow, hugelkultur beds increase surface area and retain more water than a regular garden bed could.
In this sense, you’re reducing water and wood waste, as well as sequestering the carbon from the air of your site, and replacing it in the soil.
Hugelkultur is an exceptional way to create healthy beds that provide plant food for a really long time – several years in fact – while reducing water consumption and giving your plants a real boost.
You can use your beds for many years to come, reducing the need for more labor and materials each year.
Instead, you just chop and drop at the end of the season, cover crop over winter, and replant again in the summer. Unless of course, you’re planting perennials – then you can just leave the beds to produce tasty crops for years!
Emmy Jenkins, AKA Permie Emmy, has spent many years traveling around the globe and working remotely, dipping her toes into a myriad of disciplines. Having spent several years volunteering on sustainable farms, Emmy chose to delve deeper into permaculture theory to understand the social and economic patterns often neglected in the philosophy. When she’s not planting edible gardens and frolicking the jungle, she’s consulting on projects around the world to help permaculturalists to understand regenerative ‘Fairshare’ economic patterns and to encourage People Care patterns that focus on biomimicry.