Laura Lengnick continued our series on Biointensive Gardening this past Saturday. This second installment started with a brief summary of the eight components of Biointensive Gardening, then focused on double digging and composting.
To recap, the eight components to this approach are Double Digging, Composting, Intensive Planting, Companion Planting, Carbon Crops, Calorie Crops, Seed Saving, and finally a whole system approach--as in you have to use all of the components for the approach to succeed in feeding a person sustainably.
Double Digging, described extensively in John Jeavons classic book How to Grow More Vegetables, Double Digging is simply a method for using human labor to deeply aerate and amend soil. The tools involved are an English garden spade, a garden fork and a broad fork or U-bar. Lengnick had some beautiful specimens from DeWit. These are tools for the fine art of gardening; the sort of tools that are satisfying to use for their beauty as well as their productivity.
After a number of folks tried their hand at double digging, moving the top foot of soil in our three foot wide bed over, then loosening the second foot with the garden fork, we moved on to a demonstration and discussion of compost. Ecology Action, the founders of Biointensive Gardening, focus on low technology methods for producing high quality compost either rich in nutrients or carbon depending on the beginning ratios of carbon to nitrogen. We chose to build a hot pile, using one five gallon bucket of green material/nitrogen (weeds from garden plots and kitchen scraps) to every one bucket of straw/ carbon. We spread about an 1/8 of a bucket of soil over the pile. We watered each layer. This ratio produces about a 30:1 ratio of carbon to nitrogen. This pile will be very hot, break down quickly and lose much of its mass, producing a low carbon, but high nutrient finished product, best for use as a fertilizer. With more buckets of carbon to nitrogen, we could move the pile toward a slower pile, more carbon rich and less nutrient dense.
What we realized as a garden during Lengnick's presentation was that we needed to become "carbon scavengers," as she put it. In order to create enough compost to breakdown our nitrogen heavy production and replenish our soil, we need to be providing a great deal more carbon. While we could buy straw, Lengnick pointed out that if we are bringing carbon in to our garden, we're depleting carbon somewhere else in the system. So in addition to scavenging straw from our horse farming neighbors, shredded paper and wood chips from the greater community, we also need to start growing more carbon crops. Examples are corn and sunflowers. In a true Biointensive mini farm, 60% of the 4000 square feet in production are devoted to carbon crops! That's a big reframing of the way most of us farm.
Lengnick will continue her series on August 21st at 9am at The Black Mountain Community Garden. Next month's workshop will feature Intensive Planting.