Vertical Hugelkultur

Hello all,

I have been looking into hugelkultur variations recently and have come across numerous variations, including the hugelbeets and the hugelpath ideas, but I was wondering if anyone has ever tried to do hugelkultur vertically. Logically all the hugel beds I have seen rely on the horizontal piling of wood and other woody materials before building the rest of the mound, this is the easiest method and provides the least amount of work. However, I am toying with the idea of using either all or part of the wood vertically, then driven into the ground. Obviously, this would be more work but my working idea is that the smaller diameter wood pieces can be driven partially into the soil below the mound and the larger pieces can be placed either vertically or horizontally depending on space. The central idea behind this is to improve the soil beneath the mound as well, as well as provide anchorage to the buoyant core of the hugel. I also imagine these vertical pieces of wood can act as water wicks to some degree.

A dug trench could easily have a hugel with vertical wood, but I don't really think that would give much inherent benefit. I want to apply this specifically to above-ground hugels, especially those with notably poor soil underneath. That way, as the hugel decomposes, the wooden pieces below the ground will transfer some of these benefits (microbes, water, etc.) below the pile and be more beneficial for long-term perennial planting with deep roots after the pile flattens. Since this is all theoretical at the moment, my best idea so far is to restrict the buried sections to diameters below 3 inches, like ramial, and to use a piece of rebar and a good mallet for installation. Instead of sharpening the sticks to drive down, driving down with the rebar will create the initial hole and hopefully allow the stick to drive down easily. Although I can already imagine the penetration will be difficult with extremely poor/rocky soil. The rest of the bed would be filled in after.

Has there been any work like this before? Obviously, it is good to experiment with these kinds of things but I don't want to take risks just for the sake of novelty, especially if it has been shown to be a poor idea. Please let me know if anyone has thoughts on this matter.

Eric S.

When I started my huglekulture in raised bed style, I had a whole hackberry tree to work with. This was cut into approximately 18" sections, which I stood up vertically, then filled the gaps with smaller bits of wood. It was further packed with chicken manure, dirt, and woodchips. All of which also piled on top to become the quicker decomposing planting layer.

That example is a lot smaller scale that what you are talking about. But I see no reason it wouldn't work on your scale. I feel like the logs ends in the ground would promote more moisture movement (in a good way) than horizontal logs where the top layers might dry out easier.  

The only issue I've had is colonization by inky cap mushrooms that fruit once or twice a year with great excess to the point of disrupting some of my vegetables with their sheer volume! I can't correlate vertical logs with that issue though.  

Hi Matt,

A whole hackberry tree is a lot of wood! I agree with your point about the moisture too, that's one of the benefits I hope to gain over horizontally stacked wood. The mushrooms sound like a happy accident, unfortunate to hear they disrupt your vegetable production but very interesting to speculate whether this orientation is more suitable for mushroom colonization.

Partially burying inoculated mushroom logs is a wise practice to retain moisture in traditional log culture so it would make sense that it may confer some benefits to this system. However given that any wood is surrounded by so much water-holding capacity in terms of other pieces of wood, organic matter, and other amendments like biochar, I think it will really only come into play in very dry times. However, if we think about it in the opposite manner it may wick some water downwards into the subsoil when water is in excess, which could be helpful for very saturated hugel beds. But I think any benefit there would be marginal as gravity can draw water down in most cases. Perhaps in compacted soil or very heavy clay, it might come in handy, or any other system that is poorly drained.

Eric S.

Hi all,

Wanted to update this thread with a new idea to add to this concept. Initially, I wanted to have the sticks use a pre-pounded hole created from rebar but I have come to the conclusion that perhaps a large broadfork is more suitable. The former idea was derived from a method I have seen in planting streambank trees as whips, with the rebar hole allowing the willows to root deeply and firmly on the bank. A broadfork however is a much more common tool, not to mention more efficient (More holes per use) and more accessible (Especially with the long handle). I think the only real drawback is the shallower depth, so perhaps rebar is still more useful in sites where substantial depth is preferred or where rocky and/or heavy clay prevents reasonable use of a broadfork.

I have used a broadfork before but I know there are people here who have used them for longer than I have been alive so I am curious to their opinion. Specifically over whether a broadfork would be a good choice for this concept.

Eric S.

In addition to the poles driven down into the soil, it would be beneficial to use some biochar when incorporating the poles. After this, it would make sense to use primarily liquid fertilizer like compost tea, biochar slurries, weed juice, bacterial mineral water, or some other KNF or JADAM concoction.

I initially thought to try and differ the rot resistance of the wood poles by choosing different species. But, I think as long as they're hardwoods, and not allelopathic then this consideration is not as useful.

As they decompose, I am hoping they will, at some point, connect with the other poles driven in the area through the activity of roots, fungi, and other soil microbes. Once I have land of my own I am excited to try this, especially with heavy clay and/or compacted soil, in order to determine real numbers. Things like pole spacing, time, viability, and the like. Obviously, this system will not work with root crops, certain annuals, and any crop that requires conventional tillage, but the possibilities excite me!

So much depends on the exact ecosystem and soil type.

I have actually suggested that a friend try a version of this on his heavy clay soil, in an effort to introduce carbon into the soil between existing mature fruit trees. My friend thinks he may have a layer of hard pan or plow pan which is interfering with water infiltration. It's very hard to know. I would think that with mature full size fruit trees, their roots would have broken up any hard layer, but I'm not about to dig up his yard to find out!

I have read that if you put wood vertically, and it isn't covered, there's a chance it will wick water out of the hugel bed. This is not something that would be easy to prove and the one spot I did that in an effort to stop a compost/hugel mound from collapsing onto a path, I would say that I couldn't tell if that was an effect or not. In my ecosystem, there are plenty of stumps left by former tree cutters, and again, I wouldn't say they dry things out more than the normal summer drought, and Huckleberries certainly like to germinate, grow and produce on some stumps.

I've also read about the concept of digging a hole and filling it with all sorts of compostable material in an effort to improve soil. The suggestion as I remember it, is 1 foot diameter by 3 feet deep. In my rocky clay soil, that's just not happening! However, I have done a number of holes like this, particularly near fruit trees, with mixed success. I do think the holes help with water infiltration, but I can't "prove" it. I'm lucky if I manage a foot deep and 2 feet diameter, often larger diameter, because every time I hit a rock, things get wider in order to get the rock out. I grow rocks really well!

One thing to keep in mind is that if wood dries out, and then you get a lot of rain, it floats. There has been a situation where someone buried wood in the dirt from a swale, and the whole thing slid down the hill when there was a big rainstorm after a long drought. I have buried lots of wood on my land, and I've not personally observed this effect, but I'm working at a much smaller scale than the example I heard about. What you're describing doing, seems to me to be that smaller scale and soil friction against the wood would keep it in place.

I look forward to hearing how this all works out when you find a place to try it.

Hi Jay,

I appreciate your input. In my head, this method, which I have dubbed The Spike Method, is now closer to a soil conditioning regime rather than an aspect of hugelkultur. My main goal is to use this method to break up heavy or otherwise poor soil without digging up all that earth. A French double dig or even digging holes to fill with organic matter as you mentioned, both can work but require the movement of a lot of dirt to make them feasible. That being said they are quicker than the spike method, which also still requires work.

The wicking effect on a hugel bed makes sense, and that supports another aspect I would like to get from the spike method, channels for water. Wood is great for absorbing water, and along with the decomposing wood, liquid applications, and biochar, I think soil life will flourish in that immediate area. A high density of these spikes would allow these channels to eventually connect, as well as provide channels for perennial roots into the deeper parts of the soil.

In my head, I initially thought about driving the spikes downwards in a grid fashion, and while I think that's a good guideline, I don't think it will work on excessively rocky soils. Shifting positions, as well as angles, can help avoid some rocks. I also appreciate the floating wood aspect, I have heard about that in the context of hugelkultur beds but I didn't connect it to this method. I think, as you said, that the friction will be sufficient but I will keep an eye on it in my test.

I have a few concerns moving forward. Will there be sufficient oxygen in those soil depths? And will driving the poles into the soil prove to be too laborious? Or rather not worth trading the immediacy of simply digging up and amending all that earth.

Eric S.