Something is lurking on the edge of the garden…a great mound of wood and leaves and straw is rising up right next to the barn, towering above our heads (well, my mother’s 5’0″ head, at least) and sequestering a prodigious amount of carbon. It swallowed both a winged elm stump and the brush from several fallen trees and it’s been eyeing the vermicompost bins hungrily…
What is it?
It’s the hugelmonster!!
I’m sure you’re asking yourself by now what I’ve been drinking because you’d like some of that, please and thank you. Well, I’ve got good news for you because I’m drunk on permaculture and the building of a massive raised bed that, so far, hasn’t cost me a dime.
I first came across the concept of hugelkultur beds in Toby Hemenway’s seminal permaculture book, Gaia’s Garden. It’s just a brief mention on page 84, but it was enough to capture my interest:
Wood is decomposed mainly by fungi, which we welcome into the ecological garden for their superb ability to keep soil moist, break down otherwise stubborn substances, and produce disease-fighting compounds. We can’t add much wood waste to a compost pile, but rather than burn or landfill surplus wood, we can use it to build soil too…Branches and brushy prunings are used in a gardening technique called by its German name Hugelkultur (pronounced HOO-gul-cool-TOOR), or mound culture.
I hesitate to call myself a permaculture devotee. I’m more of a permaculture vulture, scavenging the techniques that work for me and the land I’m partnering with and leaving the more complex theory and practice to the permaculture experts. Honest-to-goodness permaculture designs are complex systems that can take years to develop and implement properly. What I’m looking for are concepts that are easy to translate into the reality of my day-to-day work on the farm, are (relatively) easy to execute, and are (relatively) easy to maintain.
In any case, the hugelkultur concept fascinated me. According to Hemenway, some of the advantages of hugelkultur beds are a slight temperature increase in the bed, creating a small microclimate ideal for season extension; the retention of moisture by the decomposing wood, reducing the frequency of irrigation; and the slow release of nutrients over time, reducing the need for fertilization. And perhaps most importantly, it seemed like a good way to capitalize on our most abundant resource here on the farm: wood. Out of our hundred acres, slightly more than half is forested with mixed hardwoods.
But as interesting as it sounded, I’d just never gotten around to building an actual hugelkultur bed. Until now.
A week and a half ago I finally decided to take the plunge and I, along with our current WWOOFers Katie and Adrienne, started work on what has since been fondly dubbed “the hugelmonster.” Because we’re not just building a hugelkultur bed here; we’re building a massive one.
A beautiful winged elm used to keep watch over our oldest garden area but we lost it to an ice storm four or five winters ago, leaving an ugly stump on the northwestern side of the barn. In the interest of breaking down the stump more quickly, I decided to include it in the hugelkultur bed. Its presence played a large part in determining the placement and boundaries of the bed.
We cleared the area of large clumps of grass and debris and then got to work soaking cardboard to serve as our base weed-suppressing layer. I’m glad to have several years of experience with using cardboard boxes as sheet mulch. I’ve learned that it’s most effective against perennial weeds like bermuda and nutsedge (both of which exist in significant quantities in this area) when it’s laid out during the winter or early spring, when these warm-season plants are still dormant.
Just to be thorough, we put down two layers of cardboard–this is the first layer, nearly complete. You can see that the ground on the right side of the stump is rather sloped; ordinarily you’ll want the perimeter of your bed to be relatively level. I could have come in with a mattock or shovel and leveled this off to make placement easier.
For the bulk of the hugelmonster, we used a variety of logs, gleaned from trees felled by storms and rot. Some of the logs we used were so big that they couldn’t be split and would have otherwise been destined for the outdoor burn pile. I saved the half dozen largest to serve as seating around our burn pile/bonfire pit, but the rest went into the bed. Now instead of releasing carbon during burning, they’ll help sequester it in this bed.
The great thing about hugelkultur is that it doesn’t matter whether the wood is fresh, seasoned, or even rotted. A few of the older logs had mushrooms growing out of them, which is a great sign–the existing mycelium will get a jump start on colonizing the bed and beginning the work of breaking down the wood.
There are a few types of wood you should avoid when building a hugelkultur bed: cedar or similarly rot-resistant woods, and allelopathic wood like black walnut. We did end up with a few small and medium pieces of cedar in the hugelmonster, but I’m not concerned about it since I’m not looking for rapid decomposition in this bed; I don’t expect to plant anything in it this year. (More about why that’s the case in part two.)
The first layer was very distinct. In retrospect, it might have been a better idea to lay all the logs parallel instead of making a border first and then filling it in. I also think it would have been better for long-term weed control to leave an even bigger cardboard border around the logs. Fortunately, I have two more stump sites that I’d like to turn into hugelkultur beds, so I’ll modify my technique accordingly on the next bed.
Remember that slope on the right side of the stump? It was hard finding logs that would stay put there without some kind of support, so I improvised and pounded in five sharpened sticks left over from making labels for the fall garden last year. It worked surprisingly well and since they too are wood, they’ll decompose over time and just add to the bed.
The second layer was also distinct, but by the time we got to the third layer everything was starting to blend together. My type-A perfectionist control freak side started to get worried (“are we doing this right?”) but then I remembered: there is almost no wrong way to do this. Seriously: your bed can be 2′ x 2′ x 2′ or it can be 12′ x 6′ x 5′, you can use brush and small branches or giant logs (or both!), you can purchase a lovely layer of topsoil to finish your bed or you can just throw a bunch of free or cheap organic matter (stay tuned for that part…) on top and let it break down over time. It’s all fair game.
We ended up with five or six layers of logs, depending on how we counted. As the pile rose skyward, it became more like a jigsaw puzzle; we frequently arranged and rearranged logs to find the best fit. Towards the end, when we were putting the last few logs on the top, we even had a minor collapse on the left side of the bed. The sudden weight at the top dislodged the exterior logs from the second and third levels, but we were able to replace them and then wedge smaller logs in around them to keep them from moving again. On the whole, however, the bed is remarkably sturdy, as evidenced by the above photo of Katie on top of the third level.
The bed will lose a lot of height as the logs decompose, so the current steep slope will be tempered over time. We managed to accomplish all of this in one day with three people, so just imagine how quickly a smaller bed could go!
Next time: things start looking really weird when we modify a cob building technique and turn the hugelmonster into a porcupine, fill in gaps with small logs, and start throwing organic matter on the bed…