Hugelkultur is a method of building planting beds by covering wood with dirt; big piles of wood and sometimes other organic matter. You can dig a trench and fill it with wood, or just pile the wood on the ground and cover it. There are many different approaches as Paul Wheaton points out, and the results are impressive. This has to be one of the most low tech systems I've ever heard of.
Why would you do this? As the wood rots, it has an incredible capacity for holding water, and creates a nifty little ecosphere to promote a healthy soil web of microbes, fungi, insects and worms. Eventually the decaying matter provides nutrients to the plants and critters, and as the wood decays it helps to prevent the soil from becoming compacted. Some experts say the results can positively impact the bed for 15 to 20 years. Plus it's a very fun word to say.
I had a big pile of firewood from some dying trees we took down several years ago, and rather than starting a new bed, I decided to convert an existing raised bed planter. I've seen videos of giant Hugelkultur beds, but several permaculture resources recommended approximately 6′x3′ dimensions, so my 4′x4′ planter should be perfect. Incidentally, this is one of the same beds from the worm tower solution. I started by removing all the dirt from the planter, and went down about another foot below ground level.
When I removed the worm tower it was full of happy worm life, with worms in the tube, and hanging out of the holes in the side. There was some pretty solid evidence that the worms were venturing in and out of the tube to feed on the bacteria in the compost and bring the nutrients directly to the soil. The soil also had an abundance of regular earthworms, a big change from several years ago. I almost hated to pull this bed apart because the things we tried in past years had really seemed to work, but the dramatic claims around the benefits of Hugelkultur make it a worthy experiment.
After the dirt was removed I layered in the wood, and added a couple of buckets of compost from different stages. Avoid using wood from trees that contain natural toxins, like cedar and others from this list here – and if you find a good list of recommended wood to use, please post it in the comments for this article. I covered the whole thing with the dirt I removed, and then covered it with white clover seeds.
Maybe we'll go 'no till' and leave the clover in with the garden next year – not sure yet. I haven't seen anyone add unfinished compost, so that was a random addition, but I have several stages going, which may give a jump-start to the soil life.
Visit Brad's website, highlyuncivilized.com
Book: Edible Paradise: How to grow herbs, flowers and vegetables in any space by Vera Greutink
For bigger scale huglekultur beds please see 'Earth' – So important they named a planet after it (& how to build hugel beds) by Tim Green