Here’s what happened. I had begun reclaiming two beds overrun by spearmint by gouging out eight or more inches of soil and rocks with the intent of creating two rectangular voids to be filled later. Hard work, but it’s good work.
Then, on consecutive days, I browsed through two gardening publications at random and both had an article on hügelcultur, a strategy for creating a raised bed by heaping up branches, twigs – even whole logs – and covering the pile with leaves, grass clippings, other organic material and eventually dirt.
The idea is the mass of wood will break down slowly and release nutrients into the soil for years. In the meantime, there are air pockets for roots to roam around in and the natural decomposition warms the soil thereby extending the growing season for bean-lovers, for example.
All right then. That’s how I’ll fill the voids. I had half of the first bed dug already, so my mattock and I got to work with a new vision – gouging out two pits so I can fill them with sticks and stuff.
In every forest on the planet, twigs and limbs break off in the wind and weather, and fall to their decomposing place below. Therefore, hügelcultur. In your garden, pile limbs, twigs, wood chips and chunks as high as you can manage and mix in leaves, straw, more limbs and leaves. A taller pile will be three-dimensional, which is cool, but you also get more gardening space.
The carbonaceous nature of rotting wood means it will absorb nitrogen from its surroundings at first, but manure, grass clippings and green leaves will restore a balance by providing nitrogen. You can also plant beans, peas or clover which put nitrogen into the soil. Eventually, the decayed wood will not only release nitrogen back into the soil but add a friable texture to the bed.
Plus you would be sequestering carbon in the soil.
But wait! There’s more! The wood in your hügel will absorb and retain moisture and slowly release it essentially becoming a drip irrigation system below ground which would be a safeguard during hot, dry summer months.
The best wood for hügel mounds includes alder, oak, poplar, apple and cottonwood. Willow is good too, but if not completely dry, it might sprout. Aged (already rotting) wood is good, too. Wood not suited for hügel mounds includes black locust, which obstinately refuses to deteriorate, black walnut which contains a toxin inhibiting plants nearby, and cedar which works only if it is well-aged and toward the bottom of the pile. Black cherry also will release an unfriendly toxin.
Fungi like rotting wood, so the hügel mound might become a mushroom generator. Mushrooms in turn facilitate decomposition of the wood making the neighborhood attractive for earthworms and an active soil economy.
My plan is to add more mass over the next month and work with the weather to settle my new three-dimensional project into place. My piles are not even ground level yet, so the fun has just begun.
Another strategy would be to create a hügel mound and surround it with bales of organic straw further contributing to the slow, organic decomposition of the interior. This approach might mean the gardener would have to climb onto the bales to get to the middle of the bed, but gardening offers a return to childhood instincts, so climbing onto bales works for me. The problem would be finding bales of organic straw.
I entertain easily, so, truth be told, I enjoy bouncing up and down on the piles of branches. Gardening is therapy. My mounds will not rival the pyramids in Egypt, but spy satellites passing overhead might record the bulges of earth and wonder what is underneath. If agents arrive at my door with questions, I’ll say, “Hügel,” and everything will be okay.