DesignEarthworks & Earth ResourcesGeneral

Don’t Try Building Hugel Swales – This is a Very and I Mean Very Bad Idea

Let’s start out with a basic understanding of what full scale Hugelkultur and full scale swale based systems are. Then we can jump into what they are not and why combining them can be a very bad idea.

First, as most permies know, a swale is a ditch on contour. They are also tree growing systems, and are not designed to grow annual gardens. They do a great many things well. Swales can fill ponds, prevent erosion, create pattern framework and the big one everyone focus on, they infiltrate water. In the end though, swales are simply non-compacted mounds on the down grade side of a ditch on contour for the purpose of establishing tree based systems.

Don’t get me wrong you can get a lot out of small scale swales and swale like paths for gardening, etc. But such is not what the term “hugel swale” means in the countless minds of those who keep recommending this practice. So far we have been lucky and most of the people who want to do this seem to have not acquired the resources to do it on large scale.

Second what actually is a Hugelkultur? This is mainly an Austrian/German technique made famous, but certainly not invented by Sepp Holzer. Holzer is considered the master of Hugelkultur with good reason by the way. He says in his book, “Sepp Holzer’s Permaculture”, “do not put hugel beds on contour”. There is a very good reason for this message. Understand for a moment, that a man who has built more hugels than likely anyone else on the planet says not to build them on contour, and that swales must be on contour by their very definition.

Now let’s discuss what Hugelkultur is. Loosely translated it means, “hill culture”. In other words, it is not burying wood deeply below grade. The proper execution of a hugelkultur would be piling it up at or perhaps just slightly below grade, then covering it with soil. A true hugel is approximately 30% wood core and 70% soil. It is 1.5 to 2 meters tall; the angles of the sides are at 70 degrees.

Image from https://www.flickr.com/photos/jon_roberts/7072069873/
Image from https://www.flickr.com/photos/jon_roberts/7072069873/

The purpose of this mound is twofold.

1. Break down organic matter and build soil

2. Grow annual production while number one happens and/or growing short term perennials and nurse trees for later planting in other locations.

How do I know this? When I met Sepp in Montana in 2012 and watched him build about 4 linear kilometers of hugels, he told me so and I believed him.

I hear cries of heresy and blasphemy, but I am just telling you the way this system is actually used successfully. So strap in if you are upset now, indeed it gets worse from here. The big shocker is what happens next. One of them you may have a hard time believing…

1. The mounds over time sort of flatten and are left. At this point, the succession proceeds into long term perennial production. The key though is that a few seasons of annual cropping and short term perennials are used first. Generally in this case they remain bush, shrub, small tree, herbaceous and annual crop producers.

2. More often than above, gasp! The mound is at some point spread out and full on perennial systems are established or even grazing systems are boosted. This can produce astounding amounts of soil, the value of which if trucked in would be measured in 10’s of thousands of dollars per acre.

The primary purpose of hugels is building soil, production is of secondary concern. Getting production out of hugels makes the method practical but none the less, still secondary to the original intent. Very few edicts to the concept are even aware of why Sepp Holzer did hugels in the first place. Quite simply it was done because he had a ton of low value trees around and removing them was more costly than their value.

Something had to be done, so Sepp buried them. That is it really. I have seen Holzer build berms with no wood in them for many other reasons; some of these go straight to full tree production because they will not slump in time like a hugel will.

So why not combine the two?

First look at the goals,

• A hugel is about annual and short term perennial production in a decaying mound designed to collapse on itself over time. A mound that may in fact be spread out in the future after having built amazing soil for almost free.

Image from Jacks' Flickr, reproduced with permission https://www.flickr.com/photos/tspworkshops/8845833957/
Image from Jacks’ Flickr, reproduced with permission https://www.flickr.com/photos/tspworkshops/8845833957/

• A swale is designed to be a non-compacted mound immediately planted to long term perennial tree based systems.

As permaculturists we are trained to combine systems, to function stack and at times we take this way too far. When you force two very different techniques into one, the intended benefit is lost. These two methods are just not compatible as a single technique. They can work beautifully together, but not as a single technique. I will conclude with how to combine them so please read on and hold judgement until then.

What I want to cover next is the bigger reason swales and hugels do not go together. As permaculture practitioners and designers we should not be creating potential natural disasters in our work. In order to convey my point, lets do a bit of math.

Say we build a full on swale 9 feet wide, average depth 10 inches, length say 350 feet long. Once enough rain infiltrates or fills ponds and this swale begins to hold water, what is its holding capacity? It scares me that people are putting in these structures without doing that math.

The answer is a bit over 19,000 gallons.

And remember, about 19,000 gallons were already infiltrated into the soil below grade and quite a bit wicked up into the mound. Oh that’s right, the un-compacted mound allows for wicking, an added reason to why we don’t compact it. So the swale will wick up water, and it is very good at doing that.

Now most of you are thinking but we don’t build a 2 meter high hugel when we do a swale. I agree, but if we create the thing we call a hugel swale we put quite a bit of wood in it. Say we stack a few layers of woody material along the contour, enough to be say 2 feet high and a few feet wide, then burry it with the dirt from the swale. We now have loosely compacted soil, holding down a massive buoyant core of organic matter that is in no way locked into the soil. Just in front (downhill) of a system with 19,000 gallons of water in it when full. Can you see what comes next?

Now great joy comes and our first major rain event occurs. Thousands upon thousands of gallons of water go into the swale, much into the subsoil; we super hydrate the land and the mound too. Now the excess water sits above ground and applies pressure on the uphill side of our hugel swale. The wood core begins to float as large amounts of water seep through our un-compacted dirt and next thing you know, there she blows! You have just sent a massive pile weighing many tons flowing down the landscape. Think this can’t happen? Well I had a conversation with Mark Shepard and he told me of an instance where it did happen.

The basics were, some permies got permission to build a permaculture project at a church. They got excited about the hugel swale concept. They brought in truckloads of woody material and piled it all up on contour. They hand dug a great swale, nice sill for overflow and all included. The rain came, everyone was excited.

Image from https://www.flickr.com/photos/roblz/2445993119/
Image from https://www.flickr.com/photos/roblz/2445993119/

Next thing you know, multiple metric tons go floating down at a relatively slow speed to another building. Slow speed of movement is deceptive though as mass time acceleration equals force.

Even slow velocity makes a lot of force with a lot of mass and that was a problem here. The wall was breached, mud and water poured in. Building owner is mad, church is mad, permaculture looks bad. Not a great story huh?

Guys and gals. For all the wonderful things we can do with little risk in permaculture when you step up to earth works you have to do some math and get it checked by engineers when it is beyond your current level of experience. Let me bring some of it home to you. Say you have a catchment area of 10,000 effective square feet, some is hard, some is soft but when you do all the math the effective catchment for 100% run off is just a measly 10,000 square feet. With that you collect about 6,200 gallons of water per inch of rainfall.

Many times we are working with dozens of acres of catchment. A single acre is 43,560 square feet. When you get one inch of rain on an acre you have 24,000 gallons of water and some change. If you get a big rain event, say 6 inches, that is 144,000 gallons of water moving through your system.

Image from Jacks' Flickr, reproduced with permission https://www.flickr.com/photos/tspworkshops/8846447602/
Image from Jacks’ Flickr, reproduced with permission https://www.flickr.com/photos/tspworkshops/8846447602/

I am not saying you can’t bury any wood in a swale mound. If you put down some scrub or say a single row or two of logs, the end system will be quite stable. But that example isn’t a hugel swale, it is a swale mound with bit of stray material buried in it and that material will do little or nothing to support the system beyond may be kick starting some fungal activity and sequestering a bit of carbon. It is simply a convenient way of getting rid of some material you have no other use for.

Can you make small hugel like beds on contour safely? Yep I have done so on my own property, the majority of the wood is below grade, the mounds on contour only account for about 2,000 square feet and the hills are only 36 inches wide and were built to about 24 inches high. They were annually cropped for a season then successed to become a small orchard. The total catchment they take water from is only about 5,000 square feet and there are no “ditches” just contour paths between their four rows.

Can you make a garden with a small hand dug swale like path and use wood cores? Yep, works fine. You can do a lot with wood cores but what you can’t do is put them into contour based systems on large scale without creating potential disasters.

So how might we effectively combine them? Well the way Sepp does on his farm, he installs terraces, on the terraces he has hugels that run vertically across the short dimension of the terrace. Well a terrace is basically a big flat swale like feature. So if we are not in the Austrian Alps and don’t have such large elevations to deal with. We can use actual swales instead of terraces.

To use this pattern you would develop your swales as per normal. Use them to establish ponds, infiltrate water, establish tree systems, etc. Then in the inner swale you build hugels and use them for whatever purpose you see fit.

Now this is proper function and technique stacking. Hugels wick up moisture a lot like swale berms. By infiltrating water with the swales you begin to raise the water table in the inner swale, this gives your wood core more to wick up. Because your swales take the momentum out of the surface water the hugels are less susceptible to erosion.

In time depending on the goals and scale of the system you either use the hugels to make an amazing shrub and herbaceous layer in your system or bring in equipment at some point and spread the thousands of cubic yards of soil worth many thousands of dollars on your grazing space for almost no money.

There are indeed countless ways these two design elements can work together. However, they are and should be treated as separate techniques for very good reasons.

I will conclude with this, the master of the swale in my opinion is Geoff Lawton. I have seen him do some amazing things with swales and I have even seen him make “organic matter swale berms” but these were above grade and let water move though them. They were deposition traps, designed to break down. Never have I witnessed Geoff Lawton make a hugel swale.

The master of Hugelkultur is Sepp Holzer, have you ever seen Holzer put a hugel into a swale mound? No and you won’t either, the reason is, Sepp can do math quite well and understands the forces he is playing around with.

I know we all want to be clever and come up with “original ideas” but trust me when I tell you this is one to avoid. There will likely be a lot of objections to what I have presented here, but none will come from engineers with hydrological and civil engineering backgrounds. Please consider that before you ignore this advice.

I wrote this article because I see the concept of hugel swales tossed around all the time. And I fear in time someone is going to get their hands on a 16 ton excavator and really try to prove it. Well if it was a great idea, someone with the resources would have done it by now. Such a project will eventually harm the earth, likely harm people and it will let a lot of surplus be lost.

Folks, that ain’t permaculture.

Update

Jack Spirko clarifies his article, courtesy of his Youtube Channel

Jack Spirko also hosts The Survival Podcast and his own Youtube Channel which has been showing season two of his duck chronicles.

Jack on Facebook https://www.facebook.com/survivalpodcast

You can find other posts by Jack Spirko here.

Feature Image by https://www.flickr.com/photos/eggrole/6803888467/

Jack Spirko

Spirko founded The Survival Podcast aka TSP in June of 2008 while still working with his partner Neil Franklin. During the first 18 months of the show (June of 2008 - Dec. of 2009) Spirko did the show during his 55 mile commute from his personal mobile studio a 2006.5 Jetta Diesel TDI. The show quickly grew in popularity attracting about 2,000 daily listeners by the end of 2008, by the end of 2009 the show was being listened to by close to 15,000 people daily. At that time Spirko made the decision to take the show to a full time endeavor. Today the show attracts over 100,000 daily listeners and is referred to by Spirko as his "life's work" and his "true calling".

31 Comments

  1. Our cityscape is relatively flat. I’m working in areas with just a 7′ rise above the effective water table, plus aging drainage gullies bringing the total to around 22′. City storm drains feed a network of COE canals, engineered to recharge draw-down in the period following the Great Depression. Theoretically, (without expansive permaculture analysis,) my proposed “free local food forest” hugel-mounds will be placed in proximity to, but not within 30 t. or so of the likely flood-plane near the fragile, sandy-loamy edges of this network of urban canals. Increasing the fertility and depth of the soil profile throughout this town is critical because chemical contamination is evidenced by taste throughout the broader lowland regions.

    I am seeking suggestions and advice. The basis on my pitch weighs upon several goals. Downslope, the regenerative organic system-filter should help the environment greatly over time. Socially, it enables every grade of students and conscientious member of this destitute community to participate in a very low maintenance/no till, chop-n-drop community enriching process. This matches the city’s formally stated objectives and primary fiscal needs. Plus, almost all of the materials are already free for the asking, on site.

  2. If your beds are above the level sill spillways line and enough water can flow through the spillways I don’t see how this could be a problem.

    1. Because hydrology is the short answer.

      What does the mound do during rain events?

      In the end this whole thing comes down to people wanting to be clever and do something like take two elements that don’t belong together and mash them together.

      To put organic matter into soil in a swale system we grow trees they do the work with roots which make the system more stable, cutting up a bunch of slash and burying it in a swale mound is a bad idea. You want to do it, go ahead.

  3. Hello!

    The article was very interesting and well written. Your follow up video was satisfying as well.

    Soon im finishing my B.Sc in “sience of soil and water” in the faculty of agriculture – Hebrew university – Israel.

    In this current time I would like to do my M.S. on hugulkultur.
    There is one thing you said that cached my eye: “More often than above, gasp! The mound is at some point spread out and full on perennial systems are established or even grazing systems are boosted. This can produce astounding amounts of soil, the value of which if trucked in would be measured in 10’s of thousands of dollars per acre. ”
    I am trying to find more information about this use of hugelkultur: making high quality soil. Can you help me find some information on this subject?

    Thank you very much,
    Gilad.

  4. Thanks for the article. I learned the term “swale” from LID (Low Impact Development) training when I worked as an Environmental Scientist. We used the term swale to describe ephemeral drainages that did not have scour. These “swales”, installed for treatment of stormwater, often crossed contours at about by 90 degrees and typically had a slope of about 2 degrees.

    The Mojave Desert, where I live and worked often has natural “swales” that drain sheet flow between hills or mounds. When flows concentrate in response to development, the “swales” often become washes or arroyos which have scoured beds.

    Following the definition used by my previous employers, I have a roadside swale. Given the permaculture definition, I do not have a swale. I guess this is an example of what happens when different groups assign different definitions to the same words – miscommunication.

    I was planning on writing a blog about an infiltration trench that I built a year ago and backfilled with logs, compost and mulch similar to hugelkulture piles . So what do I call it?

    1. Agreed, I first saw the term “swale” used to describe what I now know is an infiltration area. In fact researching that led me to permaculture sites. Terminology can be confusing!

  5. What if you dug a small swale and put wood inside the swale, I mean not in the mound but in the ditch, and then cover it up with soil. So that in the end there is only a small mound of soil left en the ditch is not visible. The goal is that the wood absorbs water, decays, increases the organic matter of the soil, store water and increases soil life. The wood filled ditch is supposed to decompose and collapse over time but then it will just look like a normal swale with a ditch and on the downside a mound of soil. Is this OK? I got the idea from Gaias garden from Toby Hemmenway. it appealed to me because we had a lot of decaying wood laying around and we really needed to increase organic matter on an erosion prone, sandy hill.

    1. Marie, I am not sure how effective that would be in regard to the work ROI ratio but it wouldn’t be harmful.

      I am talking about full scale swales in this article, not foot path swales, etc. Carbon in the soil is always a good idea as long as it doens’t create problems like in the above article.

      Toby was a dear friend, I miss him. If you read something in one of his books you can trust his judgement.

  6. Great article, Jack! Thank you so much for posting this, it makes excellent sense. I am one who considered creating hugelswales, not understanding the hydrodynamics you put into play when you attempt this. I am planning some swales on contour on a lovely gently sloping but sandy hill on our property this year. We want to plant a permaculture orchard up there. There is a good deal of woody material laying about the hill I want to use (from a pine plantation that was cut down; the stumps are decomposing beautifully now, we will probably do the swales in-between the rows of decaying stumps and plant the trees guilds around the stumps). Now I know how to do the swales safely and also use the wood to add carbon and humus to the hill to build soil. We will not be doing the big wide swales as you described or build hugelmounds on the downside of the swale. Thanks again, this is very important information. We need to employ permaculture techniques wisely with sound principles in mind and not just make sh– up, LOL.

  7. Well, nice article and argument but I respectfully disagree. I’d say “don’t randomly throw hugel structures up and expect miracles”. But then again, the general idea is to know what you’re doing, which only really comes from practice. I have had excellent results controlling runoff below a garden on a slight grade using hugelkultur methiods. In our case, heavy clay soil meant nutrients would flow right on down to a pond we use for our water supply – not what we wanted. Adding a simple 40′ swale and making it spongy did two things – it re-directed surface water away from the pond and down the side of a ridge in large rains, and completely dried up a level gravel parking area below the garden. Before the swale, we had quite a bit of standing water there. Your points are interesting, but I can’t agree that hugel kultur is always a bad idea. Cheers for a nice post, thanks.

  8. Thanks for this. Yes, I was going to try one on a contour, on a hill. Yes, I have now decided against it.

  9. Well sure, you throw all them big numbers around, but my buddy Chet says we can do this and it’ll be fine — and Chet’s got his own lawnmowing business, it’s not like he’s not a professional!

    Seriously, though, Chet can go hang.
    (Chet is a fictional name for a composite character compiled from all of the “really smart guys” people get advice from before they call the Master Gardener hotline. Chet says all soil requires liming every year, that any and all yellowing of leaves, browning and softening of stems, stunting of growth, or rotting of fruit are symptoms of severe magnesium deficiency, as evidenced by his proscription to cure the plant’s ills with large quantities of Epsom salts. (Chet doesn’t know the word magnesium, usually.) Chet’s granddad grew metric butt-loads of everything flawlessly and consistently, which is wonderful but Chet’s granddad lives at least two USDA zones away.

    And now I’ll be prepared when another friend of Chet’s calls up wanting to know why they’re being sued by their neighbor.)

  10. Very new to Hugelkultur. I am interested in creating hugelbeds on our two acre property in North Texas. The land slopes south-west toward a creek. The prevailing winds are light and to the north-west. How should I orient my beds? Thank you!

  11. Thanks Jack. You mention hugels are for growing short term perennials for movement to other locations. Is it possible to use a variation of the system for long term perennials? I’m about to move to an area with poor soil and have dozens of potted trees waiting for the move. I have no intention of combining hugel beds with swales, but I am considering digging a large hole, adding the 30% timber, topping up with wood chips and soil, and then creating a gentle mound that would hopefully level out as it settled. My thinking was that the rotting timber at the bottom would provide a long term food source.
    Do you think this would be effective?
    And would the trees cope with the settling ground (considering there is 70% for them to grow through before reaching the decaying timber) or is that likely to damage the roots?

  12. THANK YOU! I was the one planning to do this… with an excavator and a skid steer… In fact, I found this article while searching for “where to find wood for hugelkulture”. Back to my plan to regrade into a crater garden. Glad to find other permies and be inspired (and warned, when necessary)! :)

  13. If you wanted to fill up a gully with soil developed through Hugelkultur, what could be done to stabilise the new soil and not create a disaster? Is the situation fundamentally hopeless?

  14. Hi,
    your page flips up and down about 25mm every 30 seconds or so without mouse input. this occurs on chrom as well as firefox. This only happens with your website. Unfortunately this makes your page almost unreadable.
    Cheers
    Joe

    1. Hi Joe,

      Are you able to send a screen grab please of the problem you are encountering. We are unable to replicate this issue.

      Thanks

      1. It’s doing it for me too (in firefox); the top banner ad, just below the menu bar (permiculture news, … Search) changes every aprox 8 seconds: cycling between “Zaytuna Permiculture regeneration course” (page content down to make space for ad), “Zaytuna plots for sale” (page content down to make space for ad), and nothing (page content jumps up). I took screenshots with the ad and without, but not sure how to attach. If you contact me at my email I’m happy to send them to you.

  15. Fascinating information. I am going to experimenting with a kind of modified Hugelkultur in some raised vegetable beds I am building this spring. I am going to excavate about 15 – 24 inches, then will place short wood rounds, cut ends facing up so that the little cordwood logs will be perpendicular to the bottom of the excavated trench or bed base. I like the idea of the water retention aspect of the whole thing to conserve water consumption, but I will not be creating the great big hills. I will fill the beds with a blend of native soil and organic materials that I have on hand.

    I’ve already experimented with this on a very small scale in some hydrangea plants for a customer I do garden work for. So far, it has worked extremely well. I just made holes about 36 inches square about 24 inches deep and placed some birch “logs” at the base of each. I layered twigs, compost, native soil, and grass clippings mixed with an acidic bark mulch. The bushes all LOVE the set up and are growing like mad. The “hills” are not extremely high, either. Only about 8 inches above grade. The native soil in the location is extremely heavy, and it was my aim to make a much more friendly environment for the bushes and keep watering needs low. Like I said, so far, so good. The bushes are doing very, very well.

  16. Hi!

    Thanks for taking the time to write this article, but I feel like you basically contradict the title of your article by demonstrating how You and Sepp and Lawton can actually include organic wooden matter with soil in the form of a Hugelkultur in front of or inside of a swale. It just depends how you arrange the wooden material. Hugelkultur does not have a defined wood to soil ratio or arrangement.

    Furthermore, I build these things all the time, I have done so for the last seven years in California in places that receive the majority of their rainfall in the three months of winter, and thus experience their maximum water loads all at once, and none of them have moved or broken or threatened anything downhill at all. They are all fine, they do great, they grow brilliant produce, and I recommend them to all my clients.

    check out my website for beautiful successful examples of non moving, abundant, safe, hugelkultur swales.
    http://www.fullcirclegardensolutions.com

    I think the name of your article is extremely misleading, and it really annoys me that people discredit the idea of a Hugelkultur swale, because they think that someone who built one incorrectly and caused a problem is representing all hugelswales.

    thank you for what you are doing to promote Permaculture in the world, but please rephrase the title of your article and just explain to people how to do it correctly.

  17. I hope you didn’t get as much pushback as you anticipated. This makes perfect sense and is important to watch for. Thanks for the article and examples.

  18. This argument would be better understood if a drawing showing contours and recommended locations for hugels were shown.

  19. This is an unfortunate instance in which the entire article could have been written in such a way that it does not “talk down” to its audience, but wasn’t. It made it hard to read, at best, and reduced confidence in the writer and the content, at worst.

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