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The Essentials of Carbon Gardening

I love the idea that my gardening can have a positive effect on the health of the greater landscape. That’s why I was particularly struck by an interview I conducted with Adrian Ayres Fisher for my podcast, Growing Greener. Adrian served as the Sustainability Coordinator for Triton College in River Grove, Ill., where her work included helping to cultivate an on-campus pocket prairie, as well as hand-to-hand combat with invasive buckthorn. In the course of this, she also became an articulate proponent of carbon gardening.

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Carbon gardening is a back-yard technique for taming the amount of carbon dioxide gas (CO2) that we release into the atmosphere. This gas is, of course, the principal greenhouse gas and most responsible for the increase in temperatures we are experiencing worldwide. Whatever your politics, very few of us want to experience hotter growing seasons and, in many regions, the prospect of more frequent and prolonged droughts. Carbon gardening addresses these concerns by encouraging plants to absorb CO2 from the atmosphere and deposit it in the soil, where it is stored as organic matter—humus.

I believe that any approach to gardening should result in a landscape that is not only sustainable and ecologically beneficial, but also more beautiful and—crucially—more fun. Carbon gardening satisfies all these parameters.  

It begins, according to Adrian Fisher, with a preference for locally indigenous plants. That’s because if you plant species native to your region, they tend to form communities of connected and mutually beneficial organisms, rather than operating as a collection of competitors. Being part of a community enhances growth and allows you to cultivate the plants with less use of artificial fertilizers, which are not only sources of water pollution but also potent emitters of greenhouse gases. Such locally adapted plants, once established, typically thrive without irrigation, too.

This emphasis on local floras, Adrian was quick to point out, means that there is no one-size-fits-all prescription for what to plant or how. A woodland garden may be appropriate for the Northeast or Southeast, but a prairie garden may be more at home in the Midwest, and what Panayoti Kelaidis of the Denver Botanic Gardens calls a “steppe garden” may best suit regions that were once short-grass prairie. Carbon gardening celebrates regional diversity. There is room in such gardens for beloved exotic plants, as well. Adrian told me that her own garden is approximately 80 percent native, with the remainder allotted to non-native plants she cannot do without.

Reducing your reliance on tilling is also a key to carbon gardening. The type of deep digging and regular cultivation I was taught to practice does lead to a quick release of nutrients because these methods encourage the decomposition of organic matter in the soil. However, that accelerated decomposition also releases CO2 back into the atmosphere and in the long term it’s a recipe for soil impoverishment. Fertility is better boosted by spreading compost over the surface of beds and letting the worms carry it down into the soil.  

This last bit of Adrian’s advice particularly appeals to me, as my aging back no longer takes well to pick-and-shovel work. Keeping plantings tucked in with an organic mulch and sowing cover crops on vegetable beds when otherwise vacant also help to reduce carbon loss from the soil. Minimize the use of pesticides, adds Adrian, as their manufacture not only releases greenhouse gases, but they also injure the organisms in the soil that play a crucial role in the sequestration of carbon.

The impact of transforming just one yard is small, but cumulatively, the effect could be substantial, especially east of the Mississippi River, where most land is privately held.  Adoption of carbon gardening could also establish gardeners in a role that I believe should be ours: community leaders for working in partnership with nature. If carbon-sequestering styles of cultivation were to become the norm among the gardening public, and from there moved into agriculture and forestry, this could reduce our nation’s annual emissions of CO2 by up to a third, according to estimates. As Adrian points out, that would be equivalent to retiring all our cars and trucks.