Air Date: Week of June 7, 1996

Steve Curwood speaks again with Living on Earth's occasional organic gardening advisor Evelyn Tully Costa, this time about the essence of soil and its properties.

Transcript

CURWOOD: It's time now once again to turn to the green garden spot with organic gardener Evelyn Tully Costa. Evelyn heads Garden Services in Brooklyn, New York. Hi, Evelyn.

COSTA: Hi, Steve.

CURWOOD: Last time we talked about figuring out where to get started in our gardens. But before we plunk down those expensive plattes of flowers and vegetables in the ground, what about the dirt?

COSTA: Very good question, Steve. Now the first thing everybody asks these days is, what about my pH levels? And I tell them, forget about those soil-testing kits and let's look at the big picture first. We really need to understand a little bit about Earth history before a pH test is going to make any sense. Now, somebody who's done a lot of thinking and philosophizing about the soil is Bill Logan. Bill is a writer in residence at St. John the Divine in Manhattan and he's an arborist. Logan recently wrote Dirt: The Ecstatic Skin of the Earth. It reads like 100 Years of Solitude meets Scientific American.

CURWOOD: [Laughs] In other words, pH is the first 2 letters of philosophy.

COSTA: You got it. For instance, in his chapter called "Stardust," he writes, "The truth is, we really don't know the first thing about dirt. We don't even know where it comes from. All we can say is it doesn't come from here. Our own sun is too young and too cool to manufacture any element heavier than helium. We are all stardust," he writes, "in fact, everything is stardust."

CURWOOD: Wow.

COSTA: Now, what did you want to know about pH, Steve?

CURWOOD: [Laughs] Well, I mean, if I shouldn't be worrying about my pH right away, I mean, what should I be thinking about?

COSTA: Well, once you figured out where the sun hit your property, you need to figure out what the plants are going to go into. Soil, in my opinion, is the basic raw material of the gardener's art. The chemical gardener uses soil simply as a means to anchor all those plant roots to artificial fertilizers. Think of those fertilizers as the human equivalent of caffeine: you might get a quick fix from coffee, but your body is depleted of energy and nutrients and you have no fuel left over for the long haul. Now, the soil is no different. Now, organic gardening on the other hand aims to enrich the soil, and it recognizes that the soil is actually a complex ecosystem like a swamp or a forest. And it's teeming with millions of organisms. Those organisms release nutrients that are required for healthy plant growth. So think of the organic matter that you need to add to your soil as good nutritious solid food. Like a hearty balanced meal that lasts you all day and keeps you healthy for a lifetime.

CURWOOD: All right. So does soil, I mean stardust, come in different flavors?

COSTA: Yep. It comes in 5 different flavors: clay, sand, silt, limestone, and peat, and these are going to vary depending on where you live. So the next thing you need to do is dig deep enough to find out where the 3 layers of soil are. For most gardeners who do shrubs, flowers, and vegetables, you need 10 to 12 inches of topsoil. You have the subsoil, and then you have the third layer. And the reason you want to dig down, let's say, about 2 or 3 feet, is to get a sense of the relative depth of each of these and their texture, and that's going to vary according to your location.

CURWOOD: Okay, and then what do I do?

COSTA: The next thing you want to do is find out what you're going to grow there, and then you can decide what nutrients, minerals, and ecosystems you need to encourage to make your particular garden thrive. You can send a soil sample to your local cooperative extension for a small fee.

CURWOOD: And then what will they tell me?

COSTA: Well, you're probably going to find out whether or not your soil is acidic, alkaline, and what nutrients are already there. But just keep in mind that the solution to most gardeners' needs is very simple. Generally speaking, if you add lots of rich, composted, organic matter, this is a surefire way to neutralize the soil, which is what most garden plants need to grow. This gets the main nutrients going in your back yard. Now, you can supplement your plot with some organic fertilizer such as bone, fish, blood meal, cow manure, fish emulsion, wood ash, and liquid seaweed. But remember, these only fine tune what should be a healthy, rich environment that you've created by adding organic compost.

CURWOOD: Okay. And what's the scoop on getting this organic matter.

COSTA: Where to get it, well, there's a couple of ways to do that. You can buy it. Manures are sold at most garden centers along with organic mulches such as cocoa and buckwheat chips. You can make it yourself by starting a compost heap with all those leaves and lawn clippings that you might otherwise stuff into plastic bags and haul out the front to be taken away. In my opinion that's like throwing out money. Just let's think about what soil philosopher and tree pruner Bill Logan says: "As the beings that make up organic life continue to exist, evolve, and cover the earth, they create a rich, stable atmosphere and rich, deep soils. Only here on earth does stardust engage in this extraordinary array of self-organizing behaviors." Okay, Steve, till next time.

CURWOOD: Bye for now, Evelyn.

COSTA: Bye bye.

CURWOOD: Evelyn Tully Costa digs stardust and soil in Brooklyn, New York. She'll be back in a couple of weeks with more organic gardening tips.