Be a Carbon Hero with Backyard Carbon Farming!
The earth is running a fever. We see it all around and we are wondering what the heck to do. Climate change is daunting, complicated and scary. The changes required are huge, and we seem frozen by it. Raising our concerns for the earth within our community and with our elected officials is paramount. We also have a host of personal choices we can make that contribute to solutions. You’ve heard people talk about minimizing their “carbon footprint”- the amount of carbon released into the atmosphere to support daily functions. An easy and effective way to offset your carbon footprint could be right outside your door. If you have land of any size that you can plant and tend, you can join the carbon farming movement, practicing land-use principles that harness the power of photosynthesis to trap carbon molecules in the soil. This keeps them out of the atmosphere, where they are causing trouble, and binds them up where they can nourish life and increase soil fertility.
Carbon and Climate
All this fuss about a little molecule called carbon. What’s the big deal? Carbon is one of the building blocks of life, an element found in you and me, and all other living things on the surface of this planet. Humans have thrown the carbon cycle out of whack by burning ancient stores of carbon (fossil fuel), and by deforesting the earth’s surface and tilling up soil, which exposes soil carbon to the air and lets those carbon molecules bond with oxygen and float away. All that carbon dioxide (and other greenhouse gasses) up in the sky have created a warming blanket. It lets the sun’s rays through, but keeps that heat from leaving again. This is causing the general warming trend and climate disturbance we are all experiencing.
Plants take carbon from the atmosphere in the form of carbon dioxide for photosynthesis, and then that carbon is stored in leaves, stems and roots. Plants feed this carbon to bacteria and fungi in the soil, either through their roots while they are living, or as the leaves and stems break down after a plant dies. This eventually creates what is known as humus- the crumbly, carbon-rich, black soil that is the envy of every home gardener. Journalist Kristin Ohlson does a wonderful job of explaining soil science for the lay audience in her book “The Soil Will Save Us: How Scientists, Farmers and Foodies are Healing the Soil to Save the Planet.” As Ohlson explains, the more the carbon is digested and used by fungi and microorganisms in the soil, the longer the chains of carbon, called humus polymers, become. As these chains become longer, they are more stable and the carbon molecules bound up in them are less likely to jump ship for the atmosphere. We can encourage the building of these long chains, and we can even entice atmospheric carbon down into the soil to join the party. It just requires a few tweaks and changes to the traditional gardening and land husbandry tactics we learned from our elders.
Five steps to Carbon Farming
Permaculture enthusiasts have unknowingly been carbon farmers for decades now, mimicking nature’s systems and producing gardens in which carbon can be sequestered and stored for long periods. The gardening methods which encourage the buildup of carbon in the soil look a lot like permaculture and marry well to organic gardening practices you may already be using. Here are five main principles of carbon farming:
1. First, do no harm. You cannot provide a nurturing environment for the microorganisms and fungi that aid in carbon sequestration while simultaneously using chemical fertilizer or insecticide sprays. Luckily, the gardening techniques we are talking about here foster plant health without the aid of chemicals. More nutrients will be made available to plants, promoting vigor and resilience. Improved soil structure holds water for longer periods and lessens drought stress. Abandoning an old way of doing things can be a big leap for us gardeners, and there will likely be a lag of up to five years between the end of artificial inputs and the full fertility and plant-health benefits one can expect from an organic, no-till, diversified farm or garden. Weaning off of chemical inputs slowly over time is probably your best bet.
2. Let it be. In order to keep the carbon happily tucked in the ground, gardeners must disturb the soil as little as possible. When you plant, work a small area right around your seedlings, or plant right into decaying organic matter. Combat erosion by watching how water flows over your property and making sure that soil is not exposed to runoff. You can plant right into cover crops that have been knocked down, rather than turning over the soil. Do not till a large area. Think about the carbon molecules like droplets of water that want to evaporate. They must lay undisturbed, under cover, to stay put.
3. Compost. Add organic matter to the soil, and don’t be shy about it! Straw, leaves, coffee grounds, your neighbors’ grass clippings, smelly, rotten lettuce you talk your grocery store into letting you take home, whatever it is- compost it and lay it on top of your beds. The amount of carbon in the soil increases each time organic matter is added, so the more the better. Imagine that you are feeding your pets- billions of them. Your soil will thank you.
4. Cover up. In areas where you don’t have plants growing, keep the land covered. Throw mulch, straw, leaves or compost over the soil. This reduces the loss of carbon molecules from the soil into the air and keeps soil microorganisms happy, maintaining moisture and moderating soil temperatures. Cover protects valuable humus from erosion.
5. Plants, plants and more plants. When we are planting the carbon farming way, we are mimicking nature. Nature never grows in monoculture. It turns out that the diversity of plants above ground improves the diversity of microbes and fungi underground. Those microscopic wonders work with the plants to create carbon-rich humus. Plant diversity can look different in each unique setting. Cover crop seed mixes are available for different regions and different seasons. When you are planning your beds, think about planting low-to-the-ground plants under taller crops. Incorporate trees, perennials, flowers, grasses, and maybe even a few harmless weeds into the mix.
Eric Toensmeier provides a wealth of information about best practices and global efforts to capture carbon in his book “The Carbon Farming Solution.” Toensmeier recommends planting woody perennials like fruit trees. Woody perennials establish vast root systems and sequester carbon in their trunks and branches. Perennials maintain a living root in the soil which provides consistent food for soil organisms.
Apply these principles in your flower beds, vegetable garden, and on the lawn. If you steward a large swath of land, your chance to make a difference is even greater. Toensmeier estimates that each year his small, 1/10th acre garden sequesters enough carbon to offset the carbon footprint of one American adult for one year. Imagine what those of us with even more space can accomplish!
In your garden
If you are already working with an organic garden, the transition to the no-till, high-diversity practices of carbon farming can be gradual and natural. If you are starting a garden bed from scratch, you will likely need to break up the ground, using a shovel or broad fork. If you need to expose the soil in this way, plant in and cover bare areas with mulch as soon as you can. Rather than planting a row of broccoli surrounded by bare earth, interplant lettuce, spinach or herbs to cover the soil around the broccoli as much as possible. A bed of tomatoes might be interplanted with carrots, onions and marigolds. Try playing with companion planting guides when deciding what shade-tolerant, low to the ground plants to put in around taller garden staples. Think of the classic “three sisters”- corn interplanted with squash and beans. Remember to mulch heavily and make as much compost as you can.
On the lawn: Store more carbon under the lawn by diversifying the kinds of plants growing with your grass. Sow clover among the grass, and perhaps consider letting the stray weed stay put. Try mowing your grass a bit taller than is conventional, or going longer between mowing. This allows the grasses to develop deeper root systems, which accommodate more microbial life. Let grass clippings stay on the lawn after you mow to break down and return nutrients to the soil. Treating a lawn with compost can improve the soil biome as well, particularly if the lawn has been sprayed with chemicals in the past. The Marin Carbon Project in Marin County, California has studied soil amendments in grassland and has shown that a half inch of compost spread over the grass improves rates of photosynthesis and increases carbon stores in the soil. The compost inoculates the lawn with beneficial bacteria, like a probiotic supplement for the yard. A lawn with a rich micro-biome will be rich in carbon. It will require no fertilizer and will hold water much better than conventional lawns.
On a farm scale: The carbon that can be captured by a home gardener is small compared to what can be achieved on a farm. Farmers may also have animals to help manure and manage the landscape. Some studies indicate that rotational grazing may improve the water-holding capacity and the carbon sequestration rates of soil. Farmers can also apply cover crop in large areas, introducing plant diversity, and bringing up nutrients from deep in the soil with “mineral miner” crops like alfalfa or sweet clover. Many farmers are now planting cover crop “cocktails” of up to 20 varieties of broad leaf plants and grasses. Jessica Wilson, a farmer on the Cumberland Plateau of Tennessee, uses techniques like heavy mulching, cover cropping and rotational grazing. Wilson describes imitating what the forest does, like putting down a layer of manure with leaves on top, and watching as worms work over the ground and break everything down. “All of this is win-win” says Wilson, speaking of how much the carbon-rich soil returns to the farmer in terms of increased fertility and increased yields. “The more we give to the soil, the more it sustains us.”
Capturing carbon in the soil is indeed a win-win for the gardener and for the earth. It improves yields, strengthens plants’ defenses against pests and disease, improves water retention, keeps compostables out of the waste stream, and all while keeping greenhouse gas out of the air. All of this, and it just doesn’t take that much effort. Mimicking nature means that the garden needs less tending from us, as we sit back and let the soil microorganisms do the work for us. In a world where we are all looking for solutions, this one is way too good to pass up.
Marina Mails, MS is a writer, life coach and gardener who wrestles with climate change, composts with religious fervor and seeks to help people find wholeness and peace. Learn more at marinamails.com, on Twitter or Facebook.