One of the core missions of Dr. Cowan's Garden is to be responsible stewards of the soil, water, and air. I want to introduce a strategy that we are using to create nutrient-dense soil, albeit in a small way, in hopes of inspiring others to experiment with this strategy on perhaps on a larger scale. The strategy is based on what in Europe and the permaculture community is called the Hugelkultur (“hill mound”), pioneered mainly by Sepp Holzer in Switzerland. 

See also: How Our Perennial Greens Vigorously Choose Life

I was first exposed to the Hugel idea while teaching gardening in Swaziland
in the late 1970s, where there were no community recycling centers, and landfills didn’t exist.  The reason, of course, was that there was nothing to throw away.  Everything the people used was sourced from the local environment; plastics or other industrial products simply were not part of the landscape.
 
As more manufactured products entered the lives of the Swazi people, they had no place to discard the waste. Confronted with this accumulation of trash, a South African man had a brilliant idea: to create garden beds, four feet wide by four feet deep, and layer them with empty bottles and other trash.  While I’m not sure I would want an old engine growing underneath my kale, given the circumstances, it was a brilliant solution.  One garden I saw had many of these beds, which were both well-aerated and held water much more efficiently than a usual garden bed. Beautiful vegetables grew atop these beds, and the village trash disappeared.  We replicated one of these beds in a small area of our garden, and the result was a beautiful and more efficient garden bed.
 
 A few years ago I was re-introduced to the idea of a Hugel, which is based on the same principle, except the trash is omitted. First, a large pit is dug (with a backhoe or other machine, if needed) about six to eight feet wide, three to four feet deep, and as long as you like.  The bottom of the pit is lined with logs, then branches, then subsoil, then topsoil, often mixed with compost or other organic matter.  If possible, the finished Hugel should be about four feet higher than the surrounding ground, flat on top with sloping sides. A generous friend in Napa allowed us to use an area on her land to make a 25-foot-long Hugel, which we topped with biodynamic compost (see our Hugel in its early stages in the photo above).
 
Hugels are always rich in carbon and low in nitrogen, so the best planting strategy is to create a living canopy.  This means growing plants and shrubs that fix nitrogen in the soil intermingled with other “layers” of plants.  The idea of layering is to increase the health of the community of plants and, therefore, productivity.
 
 The top layer is fruiting trees, the next layer is nitrogen-fixing shrubs (like Aronia and sea berries), and underneath those are perennial vegetables like ashitaba and Gynura procumbens, which tend to like shade.  Over time the contents of the Hugel break down, and it sinks a bit, but it also provides a rich organic matter deep in the soil to produce deep-rooted plants that need virtually no watering.  As labor-intensive as the creation of a Hugel is, it’s an incredibly effective way to create plant communities that will provide you with nearly labor-free food for years, maybe even decades.  
 
Our current batch of Perennial Greens Powder, due out early next week,
contains about 3 percent Gynura procumbens, grown from our Hugel experiment. The rest of the greens were grown in the Napa garden, and the moringa leaves were sourced from a wild and protected area of the Sonoran desert, the perfect moringa environment.   Gynura procumbens is otherwise known as Okinawan spinach and is renowned for its anti-aging benefits.  While 3 percent is not a large part of the mix, we have more Gynura growing in the garden, and it is exciting to have our first inclusion of Hugel-grown produce in one of our products. 
 
We hope you enjoy the inaugural gift from our Hugel as we set out to not only provide the tastiest, most nutritious products possible but also to fulfill our other core mission: restoration of our soil.

Wishing you robust health and much happiness,
Tom Cowan, M.D.