Soil Demystified

By Lauren Sims
Photo by William Cullina.

Red clay soil, like sweet iced tea, is an ever-present and oft-romanticized symbol of Southern living. However, not everyone waxes poetic about it. For many Triangle gardeners, the clay can be more of a bother than a blessing.

William Cullina commiserates.

Going through a gardening magazine and selecting plants you like may be a challenge for clay soil – some plants just don’t like to grow in clay, says Cullina, former nursery manager for Chapel Hill’s Niche Gardens and now director of horticulture at the Coastal Maine Botanical Gardens.

But don’t give up on your garden just yet. That same troublesome soil also has some great advantages. Cullina likens it to a sponge, absorbing and retaining both water and vital nutrients.

“Clay soils can be very fertile soils and rich soils,” he says, “if they are managed the right way.”

Those management techniques will be the subject of Cullina’s Feb. 12 workshop at Duke Gardens, “Beyond the Surface: Soil Demystified.”

The growth and activity that is ongoing below the ground in a garden is really more important that what you see above the ground, says Cullina. “But it’s hard for us to get a handle on it, since we don’t live underground and we’re not microscopic.”

Cullina aims to make the science of soil intriguing and accessible to home gardeners, so that they can tie it in with their everyday horticultural practices. He has helped many a home gardener with his books on plants, including “Understanding Perennials: A New Look at an Old Favorite” and “Native Trees, Shrubs and Vines: A Guide to Using, Growing, and Propagating North American Woody Plants.”

Healthy soil contributes to healthier plants and greater ecological function, and Cullina encourages natural methods to maintain it. There are organic solutions to every situation that are more effective than synthetic solutions for a lot of different reasons, he explains. And the more living material those organic solutions involve, the better.

One common practice is to add compost, or organic soil amendments, to your garden. Effective organic amendments have two components: the living and the dead. If you purchase compost directly from the supplier who produces it, you’ll receive not only the dead material but also a wide array of living micro- and macro-organisms that can feed and enrich your home garden.

It is, at its core, a simple idea. “This is just nature,” he says. “This is the way that life on earth has functioned for millions of years.”

Cullina’s soil workshop will be from 9 a.m. to noon in the Doris Duke Center. He will also make a presentation titled “The Botany of Design” from 3 to 5 p.m. For information or to register for either event, please call 668-1707 or email our registrar. You may also read more about these events and others in our full program guide (PDF), or glance at a full list of Jan.-June 2011 classes.

Sarah P. Duke Gardens creates and nurtures an environment in the heart of Duke University for learning, inspiration and enjoyment through excellence in horticulture. The Gardens is at 420 Anderson St.

Lauren Sims is a graduate student at Duke Divinity School and a work-study assistant at Duke Gardens. This column first appeared in the Durham Herald-Sun on Jan. 29.