Hugelkultur: An Essential Gardening Technique
This year I decided to get more serious about implementing small bits of permaculture design into my home garden. If I weren't a renter, I would be starting a veritable food forest right now, but since I am a renter I have to make the most I can with a small area my landlord has allowed me to plant, and grow as many annuals on it as I can.
Many people are familiar with building raised beds, but typically when people build them they simply pile up soil, maybe within a wooden or stone border, and plant in that. This is okay, but it can be improved by the very simple addition of piled up wood underneath the soil. Sepp Holzer, a permaculture farmer in Austria, builds permaculture beds six feet high, but for most of us we'll probably do them smaller. You could even dig down, pile up the wood, and then cover it in soil, thereby getting more wood in there without the height.
The principles of what this helps are simple. Wood that is buried and is slowly rotting tends to absorb water. Anyone who has tried to light a fire with wood that's been sitting on moist ground can tell from the smokiness that the wood absorbed water. Basically, water acts as a sponge, so having a mass of it in your garden bed acts as a resevoir for some water, reducing and eventually eliminating the need for irrigation. In the first year or two, depending on how decomposed the wood you piled up was to begin with, you'll see some reduction in irrigation needs, but you'll still need to water once in awhile unless the rain is frequent enough (and even then, you probably will have to once in a while. The decomposing wood also adds nutrients slowly to the soil, eventually becoming extremely rich soil that itself holds a lot of water.
I think this technique will become increasingly important in the next few years as climate patterns change and we experience more droughts throughout the continent. It also just makes your tomatoes taste better, I hear. Combined with other principles for reducing irrigation (lots of organic matter, mulching, contour, and polycrops), we can have some almost effortless gardens that build soil and biodiversity, and grow damn tasty food.