by Eric Murphy, Climate Legacy
Depending on how you tend to it, a garden can do some amazing things. In past Trillium issues we’ve written about how the right gardening practices can help local species flourish, prevent flooding in your community, and even keep away ticks. Even more is possible though, and in today’s article we’re sharing how you can even turn your garden into a carbon sink, effectively drawing polluting carbon dioxide (CO2) out of the air and storing it underground. This is great for the planet, as excess CO2 in the atmosphere is the main driver of climate change, and great for your garden too.
Though all plants soak up at least some CO2, with the right techniques a garden can increase its absorption from a baseline of about 8.5 tonnes of CO2 per acre to anywhere from 20 tonnes to an incredible 60 tonnes. Admittedly, most gardens don’t cover a full acre, but even a small backyard garden that absorbs 5 tonnes is effectively undoing the annual pollution of a gas-powered family car. With more than a million gardens spread across Canada, that kind of impact adds up fast. Below, we’ve outlined three tips to help you get started on a garden that, in addition to looking beautiful or producing tasty food, pulls CO2 right out of the air and stores it underground, enriching your soil in the process.
Choose the Right Plants, and Plant Plenty of Them!
When we think about plants that absorb lots of CO2, the first that usually come to mind are trees. Although a red maple is certainly a better carbon sink than something like Kentucky bluegrass, trees are not the only game in town. To turn your garden into a carbon sink without relying on trees and shrubs, you’ll want to focus on planting long-lived perennials and plants with deep roots. When a plant dies, much of the carbon it has absorbed is released back in the air, so long-lived perennials are ideal to not only soak up CO2 but also to store it long term. If they grow well in your area, a few great options include asparagus, bunchberry, thyme, Jack-in-the-Pulpit, anemone, harebell, trout lilies, purple coneflower, and deep-rooted grasses like bluestem and switchgrass.
Photo Credit: Adobe Stock
It’s also good to keep in mind that the more plants a garden has, the better chance it has of becoming an effective carbon sink. Long stretches of open soil, woodchips, or decorative elements like large rocks can look great, but represent wasted potential as far as carbon absorption goes.
Cultivate Healthy, Nutrient-Dense Soil
If left undisturbed, soil can store carbon for 70,000 years. To achieve this, you should plant it with deep-rooted plants like the ones listed above, or with trees or shrubs. Just as important is to avoid tilling, which, despite its benefits, releases CO2 stored in soil back into the air and only impoverishes your soil over time. Instead, consider layering a natural mulch, compost, or manure, if available, over soil to increase its nutrient density. Sowing cover crops is another fantastic way to enrich your garden and soil, especially if you have a large vegetable garden or farm.
Steer Clear of Hidden Pollutants
While researching this article I came upon a surprising study, which found urban and community gardens often have a larger carbon footprint than more rural backyard gardens. The reason? Community gardens in parks or on building rooftops typically require more added elements like raised beds, plastic tarps, or chicken wire. This is because just about anything we buy in the store, from fresh wood for raised beds or a garden trowel with a plastic handle, comes with their own carbon cost in their creation or transportation. Even worse are synthetic fertilizers and pesticides, which require oil and gas simply to make them and release CO2 over time.
So if you’re trying to plant a garden that’s truly carbon neutral or even carbon positive, you should also keep in mind the hidden pollution costs of what you buy. Choosing reclaimed wood for planters and using second-hand or borrowed tools is a subtle way to ensure your garden remains part of a healthy ecosystem, free of unexpected negative impacts. If you’ve already taken steps to make your garden a carbon sink, or if this article inspires you to do so, we hope you will let us know about your experience. You can email us anytime at .
References
- ‘How Forests Store Carbon’, Penn State Extension
- ‘How to Manage Forests for Carbon: An Introduction for Family Forest Owners’, Penn State Extension
- ‘Plant selection for green roofs and their impact on carbon sequestration and the building carbon footprint’, Science Direct
- ‘How Much CO2 Does Your Garden Capture? How To Maximize Carbon Sequestration & Increase Yields’, YouTube
- ‘What Plants are Best for Carbon Sequestration’, All Native Seed, LLC
- ‘Best Plants for Climate Change and Carbon Capture’, Organic Plant Nursery
- ‘How to plant a low-carbon garden’, RHS
- ‘Top 15 Carbon-Sequestering Plants for Your Permaculture Farm’, Permaculture Practice
