By T. Eric Nightingale, UC Master Gardener of Napa County
Your garden soil has the ability to absorb and store atmospheric carbon. This process, called carbon sequestration, has been in effect since the early days of Earth's history.
Plants absorb carbon dioxide from the air. As they process the gas, they break it apart, depositing carbon in the soil and releasing oxygen into the air. This process has helped create a livable atmosphere for humanity.
We know that carbon dioxide emissions from vehicles and industry contribute to climate change. Now we realize that there is another culprit, one we never saw coming: farming.
Modern agricultural practices involve an enormous amount of tillage. This frequent distribution of soil releases carbon that would otherwise remain trapped. Worse, clear-cutting and development disrupt the soil without replacing plant life. Concrete-covered land can't absorb carbon, and bare earth is believed to actually slowly leech carbon back into the atmosphere.
In response, many farmers are changing their methods. Using cover crops and keeping tillage to a minimum, they are working to reduce atmospheric greenhouse gases. Farming is a necessity but approaching it conscientiously can make a difference.
Though your home garden is likely smaller than a farm, you can also help support the environment. Using the same principles, your plants and soil can help sequester carbon. Growing cover crops, then leaving them as a mulch is the most accessible method. Mulch and compost will also help improve your soil texture, reducing the need for tillage.
Of course, growing plants of any kind is good for the environment as they absorb carbon dioxide and produce oxygen. But choosing California native plants for your landscape can provide added benefits as habitat and food for wildlife. Many native plants also use less water than traditional landscape plants.
If native plants are not your style, consider the many non-native drought-tolerant plants. As drought-tolerant gardening becomes more popular, even a necessity, more nurseries are carrying these plants.
Using landscaping techniques such as berms and swales, you can create a garden that incorporates plants with a range of water needs. Siting drought-tolerant plants on a berm—a low mound of well-draining soil—is the best way to assure they do not become overwatered. Building a swale next to the berm will create a space for thirstier plants. A swale is a ditch dug into the native soil which is then filled with looser soil. Water will run off the adjacent berm and settle in the swale, providing additional hydration to the plants there.
Garden design can also help reduce your energy consumption. A leafy tree or shrub on the sunniest side of your house can reduce the need for air conditioning on hot days. Some people cover the exterior of their homes in vines for extra insulation.
Another, perhaps less obvious, way you can aid the planet is to grow your own food. The plants themselves will improve the soil and air, but there's another benefit. Unless you shop entirely at a local farm stand, some of your produce was harvested by machine and transported by truck, both of which requiring fuel that contributes to global warming.
With so many people on the planet, and so much that seems beyond our control, it is easy to think that our actions don't matter. Yet small changes can produce big results, especially when we work together. Many people using a little less water adds up to a lot of water saved, and just imagine how much healthier and more self-sufficient our community would be if everyone had a vegetable garden.
Workshop: U. C. Master Gardeners of Napa County will conduct a workshop on “How to Plan and Plant a Home Vineyard” on Saturday, January 12, from 9 a.m. to 1 p.m., in Yountville. Location provided upon registration. Join our Integrated Grape Team members to learn techniques for planning and planting a home vineyard. The workshop will be held at a new home vineyard planted last year. Learn the necessary planning steps, become familiar with the checklist of activities, methods of determining the proper rootstock, selection of wine grape varietals for specific locations and estimated yield calculations. Review our calendar timeline for planning, site preparation, initial planting and timing of the first harvest for a new home vineyard. Online registration (credit card only); Mail-in/Walk-in registration (check only or drop off cash payment).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County (http:/napamg.ucanr.edu) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.