If you have spent any time in gardening circles you have probably heard about “hugelkultur“. Permaculture gardeners and regenerative farming type groups have been talking about this method for many years. It is only until just recently the more general world of gardening is starting to talk about it.
This article I will try to go over what a hugel bed is, how hugelkultur beds are beneficial, and proper materials to use.
What is Hugelkultur?
Hugelkulur is a popular term that was coined in permaculture circles. The term refers to a method in which a person will build a small “hill” by first piling up logs, then smaller branches, fill in with other assorted organic matter, then topping the layers off with a thick layer of compost.
This method of building garden beds is fast becoming popular because the basic concepts work well for filling in raised beds or planting containers.
Benefits of Hugelkultur
Hugelkultur is meant to help harness and control a decomposition cycle that happens naturally. The inner layers of wood will decompose slowly over time and improve the soil with each passing year until the inner trees become soil. The wood will be inside decaying for years and will feed beneficial bacteria, fungi, microbes, worms, and other small soil organisms.
The rotting wood is also very absorbent and will help hold moisture in place. Hugel beds have good use case if you are trying to be efficient with your water use.
One of the main reasons this method is picking up is because you can collect all the materials you need from waste matter either in your yard or from somewhere nearby. Anyone trying to quickly fill their raised beds knows that the numbers add up when trying to fill them all with quality compost. If you aren’t having your compost delivered, you might also end up with a pile of annoying plastic waste to now dispose of.
Some people have fireplaces or firepits so they like to turn their waste wood into wood ash, which is also good for the garden. Other people use the waste wood to fill space in the bottom of their deep raised beds. The wood makes a good base that will decompose over time and continually nourish the bed.
There is no tilling involved with maintaining these beds and you can basically work them like a no-dig garden except when you go to install new plants. They are also self aerated.
You ever end up with a couple fallen trees or some hefty branches and that is a lot of saved soil not being used in the bottom half of your planting bed. Many of my early raised beds were free for me to make and I didn’t buy much of anything my first few years honestly. Buying stuff can help and can make stuff happen faster, but you can get a lot done with little or no money.
My original yard had a half acre woodlot in back so in one season I’d have so much waste tree matter either in the form of trunks, branches, or leaves that it would have been easy to turn it all into mulch or hugelkultur method raised beds completely from the locally sourced materials. My neighbors were also confused when I went to haul off their waste leaves to use for my yard soil building and they were even trying to pay me to haul it off.
I’m now in a suburban living situation so sourcing waste wood is a little more interesting. Though I’ve found with a little digging around there are still people that have a lot of stuff up for offer either on Facebook marketplace or some location relevant group for local trade or barter.
Potential Problems with Hugelkultur
The obvious problem if you live in an urban or suburban environment is there are way less trees in some areas. You might end up with a decent collection of branches and sticks from the smaller trees, but not a lot of good logs. It is challenging for many to source yard waste if their yards do not create sufficient “waste”.
After you source your hugel materials you have to have the physical health to do the labor of chopping and moving around the logs. They are a lot more labor intensive than just throwing in some compost or soil. Then in the first few months after installation they will start to drop down in spots and need compost refills as the mound settles in.
The other issue that used to be a problem for me was pests. In zone 7b nearly any tree in my woodlot that had spent any amount of time on the ground had a high chance of already having some termite activity. You don’t want to have termite-infested wood material being installed anywhere close to your house. I don’t have this problem now on my property in zone 4b. This property poses other new challenges.
Another thing that is particularly hard when trying to do with hugelkultur in a suburban environment is the challenge of avoiding pesticides and herbicides. For an organic garden, these chemicals often harm more than they help.
The more traditional design for hugel beds is a hill with sides that slope up to a point on top. If using that design it can be harder to work the plants at the top depending on the height and they are also more exposed to high winds.
I do my beds more in a low mound style design and things work well for me.
How to Fill a Raised Garden Bed Hugelkultur-Style
The first step to filling your hugelkultur beds is to put your larger and denser materials, like logs, on the bottom. The next layer is a coating of your small twigs and branches to fill in around the logs then top off that off with a coating of grass clippings, shredded paper, cardboard scraps, or shredded leaves. The last layer should be a very thick layer of compost and soil.
The compost/soil layer should have a depth of 12 inches to give you space to add plants where the plants have a lot of compost to send their roots down into. It takes a while for all the woody material to break down.
When filling garden beds you have to take all of this into account. If your planter boxes have show sides then you wouldn’t use much of a wooded under layer. Hugelkultur is more preferred when your planting beds are very tall and very deep.
If you are starting from scratch and want to do more tradition hugel beds then all you have to do is put down cardboard to help mark the space and pile stuff right on top of it.
What to Use to Build Hugelkultur Beds
A lot of materials work well in a hugelkultur bed. But for a more detailed list you want things like:
- Logs and stumps
- Branches, sticks, twigs
- Wood Chips
- Hay or grass clippings
- Mild manures like worm or rabbit
- Organic yard waste
- Paper or cardboard
- Kitchen scraps
Can I Use Any Wood for Hugelkultur?
A wide variety of trees are great to use for hugel beds. In terms of hardwood trees you can use oaks, maples, apple, beech, alder, poplar, sweet gum, etc. If you have soft woods you will do well from the wide range of conifers like pine, spruce, and fir. You don’t have to stick to one tree type and can feel free to mix and match your woods as you desire.
All of those tree suggestions decompose either quickly or slowly and have a very important factor that is considered. Some trees have a chemical defense to them that help remove competing plant life in check and are distinguished as allelopathic.
Each tree has its own allelopathic rating ranging from mild to strong allelopathy. Good examples of high allelopathic trees are things like black walnut, eucalyptus, American elm and red oaks. Some trees suppress in different ways where it is just the leaves that are growth inhibitors and not the trunk or branches. Other trees suppress via their roots.
Then there are trees that don’t decompose well. Trees like cypress and cedar have a high rot resistance and do not break down well or quickly.
As you have noticed there are a lot of benefits to the hugelkultur method of filling a raised bed. If you have access to a lot of yard waste materials you can get a bunch of rich planting spaces started for next to nothing and help conserve water which is a big deal these days as a lot of the US is experiencing droughts.
I’ll be adding more valuable information so thank you for stopping by! Happy digging.