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.

Three unexpected volunteers showed up in the garden recently and finished double digging two fifty foot beds. Another group of volunteers, arranged through United Ways Day of Caring, planted celery, beets and rutabaga. These beds will be covered with hoop tunnels to extend the plant's growth (and harvest!) long into the Winter season.

Picture credit: Annie Price

Inspired by our Biointensive series with Laura Lengnick, I've continued to implement Healthy Soil Practices into our garden design. The beds pictured have grown strawberries for the past three years. The yields have consistently been abundant thanks to the help of volunteers rejuvenating the plots each year by thinning the plants down to one plant every six inches in rows two feet apart.

Despite good yields, I wanted to give the soil a break and rid the site of many of the invasive weeds (mugwort and grasses in particular) which have inhibited yields in portions of the beds. To begin, I had volunteers double dig the beds, which are each three feet wide and stretch over 50 feet. Then during a major garden work day I had volunteers build the windrows pictured.

We started by laying sticks on the soil surface then adding a layer of green material (weeds pulled from a neglected community garden bed), then a layer of straw and a sprinkling of soil. The soil acts as a microbial inoculant to the pile. As Laura explained in her first lecture, one tablespoon of healthy soil has more beneficial microorganisms than there are people on the planet! After we added all the layers, we watered the pile well. We continued building the pile until it reached a height of around 3 feet.

The pile will remain on the bed until next Spring when I will incorporate it into a number of beds. The beauty of this system is that it expands the scope of how to use a bed in the garden and how to meet the standards for healthy soil.

I love walking by these windrows; not only are they beautiful in an aesthetic sense, but also in an organizational sense. I've taken compost out of the bins and directly into the garden.

Since finishing these windrows we've begun building a windrow on another bed which has not been double dug yet and in which we grew early potatoes. After digging the potatoes, the ground was hard and formed large clots. I'm curious to see how building the windrow on this poor aggregate will change the soil structure.

Another difference in this second windrow is that we are able to use carbon produced in the garden--corn stalks. The first windrow was built with purchased straw--which ultimately means our garden fertility depletes soil fertility somewhere else. I am tentatively estimating that we will be able to produce enough compost from our cornstalk windrow to feed all 16 of our 400 square foot beds in the Plant a Row for the Hungry portion of our garden.

Picture credit: Annie Price

Click here to view a PDF of Laura Lengnick's power point presentation on Biointensive Gardening.

Laura Lengnick, PhD Soil Sciences, Director of Sustainable Agriculture at Warren Wilson College shared the following four basic practices for soil health at her presentation to the Community Garden on June 19.

Keep it covered.
Keep a dead mulch such as straw, pine straw, leaves, etc. on the soil surface or create a living mulch by densely planting crops so that mature leaves overlap. Lengnick shared that this technique is particularly helpful because the leaves create a carbon trap, making photosynthesis more efficient and preventing weed seed germination.

Disturb as little as possible.
Tilling soil dramatically disturbs soil health. Soil disturbance encourages weed seed germination, disturbs the billions of occupants living in the soil and interrupts the mineral cycle.

Keep it right side up
Healthy Soil has large concentrations of aerobic bacteria in the top 3 to 6 inches, gradually shifting to anaerobic bacteria the deeper in the soil structure. There are as many as 1 billion organisms in 1 tablespoon of good soil. In general we want to promote aerobic environments, said Lengnick. We want to maintain the gradient from aerobic to anaerobic environment. When we turn the soil, healthy topsoil will die, which takes a while to recolonize.

Feed diverse organic materials
In other words, like us, soil needs a balanced diet. In the case of soil we need to feed it carbon rich compost, manures and a mix of nitrogenous and carbonaceous cover crops such as legumes mixed with grains in a 70 to 30 percent ratio.

Healthy soil is the immune system of your garden. It can reduce soil born diseases, provide a better home for beneficial organisms, store, protect and even produce nutrients, and detoxify harmful substances. Healthy soil is 50% space. A small increase in soil tilth creates a large increase in water storage capability. Follow these simple practices and your soil will produce healthy plants which will in turn produce healthy people.

This weekend from 9am until all the food is gone, I will be offering free cooking demonstrations highlighting what's in season this week at the tailgate market: cucumbers and yellow squash. Check out Goddess in the Kitchen for recipes.

On Saturday morning Laura Lengnick, Ph.D Soil Sciences and Director of the Sustainable Agriculture Program at Warren Wilson College, delivered a power point presentation on Biointensive Gardening, as created by John Jeavons, author, How to Grow More Vegetables.

Lengnick began by laying the context for her presentation. Lengnick has been involved in the Sustainable Agriculture Movement for 25 years. In recent years she turned her attention to The Transition Town Movement. I awoke to the impact oil had on agriculture and how much fuel agriculture uses, she said. In the conventional production of food in the USA, we are using seven calories of fossil fuel to produce one calorie of food. In the last 150 to 200 years we have burned through 70 million years of plants converting sun energy to chemical energy. We are halfway through the available supply. We have reached what is known as Peak Oil and what the Transition Network is attempting to address one community at a time.

Lengnick stated that the twin challenges of the 21st century are Peak Oil and Climate Change. We have reached the point when we have used up 1/2 of the all the oil we will ever produce. "All the easy oil and gas in the world had pretty much been found." William J. Cummings, Exxon-Mobil spokesman. And it isn't the last drop that matters, Lengnick emphasized. As soon as we reach Peak Oil, which the United States did as an oil producing nation in the 1970's, there is an immediate price increase which has a huge impact on our oil driven economy.

Regarding Climate Change, Lengnick emphasized that she is not a Climate Change scientist. However, regardless as to whether you believe the reports about climate change, you can look at historical data that shows that this period, in which we developed modern agriculture has been a period of unusually stable climate. We assume that a crop that does well in a particular zone will continue to do so. Yet if you look at charts mapping planting zones for North America over the last 30 years or so, and you will find that our hardiness zones are steadily marching North. This means adapting to new insect and fungal attacks as well as finding new species adaptable to the new zone. What scientists have found is that weeds, not domestic crops, are the quickest to adapt to the new zones.

Peak Oil challenges one assumption of modern agriculture: there is a continuous global flow of materials, energy and wealth, while Climate Change challenges the other assumption of modern agriculture: climate is stable.

Lengnick continued her discussion by pulling up a slide entitled, "PEAK EVERYTHING?" As with oil we are reaching peak water. Although a renewable resource, we are using water at an unsustainable rate. She also cited studies that reveal we may reach Peak Phosphorous levels by 2030.

"We are really facing serious challenges," stated Lengnick. "But in challenges lie opportunity." In Lengnick's perspective this challenge requires a paradigm shift from "command and control," to "adaptive and responsive."

We have to understand, predict, manage and adapt to change, stated Lengnick, citing the work of Brian Walker and David Salt, authors of Resilience Thinking.

Lots of the characteristics of sustainable agriculture fit with the indicators of resilience thinking and resilience systems, Lengnick continued. Soil Health is key to resilience. Healthy soil promotes four processes responsible for conferring resilience.

1. Energy flow (It could be said that all wealth on the planet is derived from photosynthesis.)
2. Mineral Cycling (Healthy soil not only produces biological fertilizers but also removes toxins)
   
3. Water Cycling (Healthy soil captures and stores water)
   
4. Ecosystem Dynamics (Pest suppression through plentiful beneficial organisms)

And here Lengnick turned her presentation to Biointensive Gardening, a system of 8 practices which may be the solution to the Twin Challenges of the 21st Century.

John Jeavons created Biointensive Gardening in the early 1970's as a response to what he considered one of the most important and most destructive practices on the planet: feeding people. Over the years, his program Ecology Action has determined that compared to conventional large scale agriculture, Biointensive Gardening uses 80% less water, 50% less mineral inputs, and 99% less fossil fuel energy. He uses as Wendell Berry puts it, the world's greatest untapped resource: people.

Biointensive gardening produces 2 to 6 times more food on about half the amount of land. In the US it takes 20,000 square feet to grow one person's diet, in developing nations 16,000. By the year 2020, it is estimated that developing nations will have only 9,000 square feet per person for food production. Biointensive Gardening requires only 4,000 square feet to produce a vegan diet per person.

Finally, and perhaps most importantly, Biointensive Gardening builds the soil up to 60 times faster than in nature. Which brings us back to the significance of this solution--it instills resilience.

Laura Lengnick will be presenting to our garden community again on July 24 and August 21. These hands on workshops will further introduce Biointensive Gardening, covering the elements of Double Digging, Composting, and Intensive Planting.