Some hours ago–never mind how long precisely–having little or no email in my inbox and nothing particular to interest me at work, I thought I would dig about a little and see the turfy part of the world…the idea being to spend the cooler hours of the day seeing if I couldn’t install a self-sustaining raised-bed wood garden, sometimes known as a hugelkutur. A hugelkultur is basically a stack of wood–ideally six feet high–with sloping sides and upside-down turf laid on top of the displaced soil. The wood stacked under the soil/turf acts as a compost to provide both nutrients and water to whatever you decide to plant there as the layer of soil on top gradually expands/deepens through natural biotic breakdown.
If you’ve ever walked in an old growth forest and seen a surprisingly straight row of young trees growing out of the rotting remains of a fallen giant, you get the idea. A hugelkultur just requires human hands instead of a stiff breeze to get it started. Our local utility company came through about a month ago and pruned the trees back from the overhead wires, leaving piles of logs that few of the neighbors have dealt with yet, which gave me a ready supply of logs, mostly pine, which nobody wants for their stoves. Not surprisingly, no one said no when I asked if I could take the logs off their hands.
So, I’d never done this before, and if I did it again, I’d do a few things differently, but all-in-all, I’d rate my effort a solid 4 out of 10, and I suspect the resulting structure will be providing habitat for bees within two days and for vegetables or perhaps flowers within two years. The main benefit of a hugelkultur is the same as composting your food waste, grass clippings, and leaves: why pay to have potential nutrients hauled out of your yard and then pay again to add nutrients to your yard artificially–polluting groundwater and the air in the process. By stopping such irrational behavior, we can all contribute to cutting down on nonpoint source pollution, and maybe save a few bucks.
In my case, we also have in large population of skunks where I live, and the last two years the resident bees that pollinate my neighbor’s garden (my current source of peppers & garlic) have been dug out of the ground and eaten in the night, we suspect by these same stinkers. Today’s big pile of dirt-covered logs was already attracting several species of bees by the time I finished building it, so hopefully they will move in and get to work on the vegetables next door. (Safety tip: a hugelkultur is going to attract insects, rodents, snakes, and who knows what all–build it as far from the house as you would any compost project.)
So, here’s the quick history of the construction:
I have a natural swale in my yard where sedges choke out the grass, so it seemed the best spot to use, to accelerate rotting of the wood and for adding maximum moisture to the soil. It’s said if you build it big enough (and properly), a hugelkultur (OK, it’s German for “hill garden”) can go six months without watering, which is nearly as long as New England’s growing season.
I dug down roughly six to eight inches, then raked it level. Easy peasy. I put the longest logs alongside the pit to guide my digging to size.
Ideally sod is supposed to be cut back and rolled up, then unrolled upside-down on the top of the finished hill, the idea being the roots will hold it and the dirt under it in place. In reality, the sod in my yard and the underlying organic layer is pretty thin and poorly developed. This is the case throughout New England due to 400 years of cultivation–and particularly the post “Green Revolution” years when fertilizer was replaced the work of soil conservation–as well as 100,000 years of glaciation. (Nantucket? Please send New Hampshire’s soil back. Canada? We have your boulders (glacial erratics)–please pick them up at your convenience.)
(<– More evidence of past turbation in my yard: a transfer print.
Somebody call Liz J. Abel ASAP for the instant ID.)
After digging, stack. I started stacking with the big stuff.
After putting in the big stuff–the idea being that the larger logs will hold in the smaller and allow for stacking into a rough pyramid, I got some yard debris–small sticks, rotting leaves–and tried to “caulk” the logs so after the soil is thrown on top, it won’t all just wash into the interior during the first good rain shower.
In retrospect, it would have been a better idea to both caulk with twigs and also to throw in a layer of dirt between every layer of wood, like the mayonnaise between each layer of vegies in a Russian bride salad, to ensure some soil with its starter biotics was contained throughout the layer. I did not do that, but would do that if I built another one of these things.
The wood I gathered had mostly been lying around for less than a month, so it hadn’t started to decay much.
However, I did find a pile of logs which were already considerably decayed, and was happy to shunt them into place throughout the structure. Check out the fungus.
<– Fungus is your friend.
The more rotten the wood, the quicker the breakdown of nutrients will happen.
After that, it was just a matter of piling on logs/caulking/shunting until I got to a height that seemed to work. Then, throw the dirt back on and try to lay the crumbling pieces of sod upside-down on the whole thing for the resulting structure:
So, what do I have here, really? A 7×4-foot square pile of logs, roughly 3 1/2-feet high, covered with dirt to (hopefully) speed their transition into “seed logs” to provide nutrients for growing…something.
The aesthetic, classical pyramid shape featured in the illustrations on the first link above did not happen–such is the fate of eyeballing it. Stating the obvious, a 7×4-foot base does not result in a 6-foot high pyramid on which soil is going to stick (Sorry, Snefru, ain’t happening), and given the poor state of my thin-rooted sod, to build a structure that would have kept the soil from washing down the sides would have required a wider base than I was willing to turn over–got to leave room for badminton, after all.
Not a bad way to spend the morning, and if you’re not in a hurry for results, not a bad way to usefully dispose of the logs Unitil Corporation of New England leaves strewn up and down the streets in the wake of its once-a-decade pruning.
I suspect what I have probably constructed is a giant bee hive, which is fine because the neighborhood needs one. The skunks may dig under it, but the tightly-caulked logs should likely prove too much for them, not matter how many tasty grubs they can smell inside. Will the inevitable chipmunks, mice, and shrews bother the bees? Time will tell. Will this ever be a garden? Check this spot for infrequent and irregular updates.