Feature, Garden Like a Boss

Grow Your own Carbon Credits!

By James Loomis

Everything you need to know to get started in DIY carbon sequestration.

It’s impossible to be a self-aware human being in this day and age and not acknowledge the effect we as humans are having upon the atmosphere. In particular, the accumulation of carbon dioxide and other greenhouse gases in the atmosphere is having a dramatic effect on the earth’s climate.

Much ballyhoo is being made concerning how to remove this excess carbon from the atmosphere, and an increasingly wide array of complex solutions are being paraded by the world’s scientific community. From skyscrapers that act as monolithic air filters to reinjecting the carbon from power plants into the ground, these strategies have a place in helping to remediate the effect of industry’s contribution to air pollution.

But I’m not here to talk about them, I’m here to talk about us: As a network of organic gardeners and farmers, we have the ability to remove and sequester carbon from the atmosphere with far less work and cost than any high tech approach could hope to.

How is this possible? The power of plants, my dear reader, the power of plants.

Billions of years ago, when Earth was an infant, the atmosphere was made up of mostly carbon dioxide. Toxic and hostile, the earth was lifeless and scorching. When the first life appeared, (due to the first spark of evolution, God, aliens or some combination of the three), one of the earliest forms was cyanobacteria, single celled organisms capable of photosynthesizing. Photosynthesis is literally the process of using solar power to remove carbon dioxide from the air, rearrange the carbon atoms into sugar and starch molecules and release oxygen as the waste product. If one were to create such a product today, it would surely make the cover of every scientific publication on the planet.

After this photosynthesis revolution occurred, it was party time on planet Earth for cyanobacteria. For billions of years, they multiplied, photosynthesized and died, pulling countless metric tons of carbon from the atmosphere.

As they died, they contributed their bodies to the increasing amount of small mineral particles from the constantly eroding rocks, and soil was born.

These cyanobacteria gave way to more and more complex forms of plant life (again, due to either evolutionary mechanisms, God, aliens or some combination of the three). A slow but steady process, it took nearly four billion years of this process to create enough soil for the first trees to inhabit.

Our current layer of soil topping the earth’s crust is testament to a truly magnificent legacy of plants and this process. All of our “fossil” fuel is the stored accumulation of billions of years of solar energy and sequestered carbon, which had been safely tucked away under the earth’s surface for millennia. The earth’s soils still contain more carbon below ground than all of the life above it.

Now, I’m not here to rant on and on about how we’ve been releasing it, by burning fossil fuels or ravaging topsoils, because 2017 is the year of solutions for me. I’m here to talk about how we as gardeners can accelerate this natural carbon sequestration process in our soils. In fact, as an organic gardener I often measure the quality of my soil in the amount of organic matter it contains, and organic matter is simply the recycled carcasses of once living organisms. As we build soil, we are sequestering carbon, and the math on how much we can sequester is astonishing. In fact, more and more often this new approach to intensive soil building in agriculture is referred to as “carbon farming,” and is adding another layer of income to farms through the selling of some of the most reliable carbon credits on the market. Recent studies have found that adjusting our approaches to land stewardship in this regard could halve the CO2 gap!

However, while the simple action of growing plants pulls carbon dioxide from the atmosphere, as plants decay they also return some of this carbon, which is part of the carbon cycle of the planet. When fields or gardens are tilled, large amounts of carbon is oxidized and released, and the living organisms are killed, releasing yet more.

If we want to hold on to as much of this carbon as possible, then we need to encourage the processes, and the organisms, that sequester it the most effectively; the growth of plants and their roots, and the growth of fungi.

1. Never till your soil. As mentioned above, this oxidizes soil carbon, decimates massive amounts of soil life and destroys soil structure, which is key to retaining soil carbon. It also releases more pollution from the machine doing the tilling! While most till to “aerate” the soil and kill weeds, the soil will always collapse and compact to a greater degree than before tillage, and the process will optimize the soil for weed growth.

Rather, cover the garden with a thick layer of mulch in the fall, and cover with a generous layer of compost in the spring, then mulch again once plants are tall enough. Mulch and compost protect and enhance topsoil, and the life in the soil will integrate these materials into even more life and soil organic matter. A dedicated mulching and composting regimen, in absence of tillage, will result in a weed-free, perpetually fertile, gloriously friable soil.

2. Leave roots in the ground.  While it can be tempting to pull plants at the end of their life cycle, a more appropriate technique for soil stewardship is to chop them at their base, leaving the roots in place. This serves to leave the carbon that makes up the root tissues in place, but most importantly leaves the fungi and other organisms undisturbed, allowing them to go to work transforming the root tissue into humus. Humus is an incredibly long-chained carbon compound, and stabilizing soil carbon is our goal in this whole process.

3. Encourage and protect beneficial fungi. No other organism on the planet can sequester carbon more efficiently than fungi. Mycelium is the vegetative body of fungi, and the individual strands are known as fungal hyphae. For all practical terms, these hyphae are incredibly durable hollow tubes of pure carbon, and the fungi in healthy soils have the capacity to sequester more carbon than trees! In fact, some studies have found that fungi account for 40 – 70% of the total carbon sequestered in arboreal forest systems.

In addition to storing carbon in a stable form, the presence of healthy mycelial networks in soils enhance the overall health of these systems, by transporting nutrients, water, and information over comparatively large distances.

While #1 and #2 above serve to protect fungi, we can encourage the growth and vitality of fungi by keeping appropriate areas of our yard under a deep layer of wood chips. Garden pathways, peripheral areas, play areas, or any area currently neglected and weedy is far more manageable under a deep layer of wood chips. Wood chips can easily be acquired for free in an urban area from local tree services. A deep mulched area is visually attractive and will conserve moisture, protect and build soil and be weed- and maintenance-free, as well as serve as an ideal habitat for beneficial soil fungi. In permaculture we call that stacking functions, and in that regard, a deep woodchip layer simply knocks it out of the park; Boss move right there friends, Boss move.

4. Plant cover crops. Your garden should always be growing something, whenever possible. A cover crop is simply a nonfood crop, grown for some characteristic that enhances the soil—adding organic matter, nutrient accumulation, weed suppression, etc. By never having your soil idle, you are keeping microbes happy, pulling more CO2 from the air, and constantly building soil. When those cover crops are turned in, we are adding a tremendous amount of organic matter, and it’s far easier than hauling in amendments!  There’s a reason cover crops are referred to as “green manure.”

James Loomis is the Green Team farm manager for Wasatch Community Gardens.

This article was originally published on January 30, 2017.