Air Date: Week of July 19, 1996

Living on Earth’s resident organic gardener Evelyn Tully Costa answers recent listener questions about carpenter ants; lead in soil; and horsetail plants, in this garden “advice column" of the air.

Transcript

NUNLEY: For many of us home gardeners, things are slowing down a bit these days on our little patch of earth. Most of the digging, the soil preparation, planting, weeding, mulching, pruning, that's all behind us. And the big payoff of the late summer and fall harvest is yet to come. It's a good time to sit back, relax just a little, and take time to look into some of the questions we've just been too busy to get to till now. Like, whether some bugs that are causing us fits in our gardens might also be causing problems elsewhere. Or why the tomatoes on the other side of that fence look so much better than ours. To help us answer some of these questions we're joined by Living on Earth's very own organic gardener, Evelyn Tully Costa of Brooklyn. How are you doing, Evelyn?

TULLY COSTA: Hello, Jan. So, I hear the grass is greener in your neighbor's yard and you're wondering why.

NUNLEY: Ah, but the crabgrass is greener in mine.

TULLY COSTA: Ah, don't worry about it. But I understand that some listeners and Living on Earth staff have burning questions of their own today.

NUNLEY: They certainly do. Our first question is from one of our listeners, Marianne Reynolds of Skillman, New Jersey. She wants to know how to get rid of carpenter ants. It seems she lives in the woods along with the ants who are sort of hanging out in her compost heap and some of the railroad ties and in her herb garden.

TULLY COSTA: Hmm. If Mary Ann has carpenter ants in her garden, that's okay. But she's got to be careful to keep them from nesting inside the house. Now these ants love to live in soggy, rotting wood, which you wouldn't want to find out is one of your support beams. So to avoid infiltration she can ring her house with boric acid or diatomaceous earth, and she should keep firewood elevated, with breaks contact with the soil, and this promotes air circulation. If she has any rotting window or doorframes she should replace those immediately. Now, how do you know you have carpenter ants in the house? Some signs are slit-like holes in the wood and they have droppings that look like sawdust. And even sometimes you can hear them kind of crackling away inside their burrows. Carpenter ants have wings and they leave their nests to search for food, so you can trace them back to their nests. You can drill holes, once you find the problem area you can drill holes around the infestation and blow diatomaceous earth or boric acid into the nest.

NUNLEY: All right. Dan Grossman, who's one of our freelancers here at Living on Earth, wants to know about lead in the soil. He's heard it's okay to eat fruit but not roots out of tainted soil. Now is that true?

TULLY COSTA: Well, that's such a really common question these days, I'm sorry to say. And it's also one of the first ones that most of my clients ask when they're considering their garden's edible future. Now flower gardens aren't really an issue unless you've got young children digging around in the dirt and you're worried about them eating it. With vegetables and fruits, though, that's another story, and I wouldn't take any chances. So the first thing to do is to get your soil tested by your local agricultural extension service or the Health Department. Now, read their guidelines carefully. But beyond that, if you suspect that there's any construction or dumping that took place in your lot, or the test shows the soil's only marginally safe, I would spend the time and effort excavating that bad stuff out of there. Then you can build up your own organic soil and you know it's back there. Meanwhile, I wouldn't eat the fruit or the roots if I suspected lead in the back yard. Now, if the soil tests fine but you live near a roadway and you're worried about lead and other pollutants, you know, blowing onto your food, this is what I think you should do. You can wash off your fruit and your vegetables with a little vinegar, two and a half tablespoons to one gallon of water, or half that amount dishwashing liquid. The other thing you might think about is planting a solid hedge of privet or even a quince to keep out some of the fumes. Now just remember that lead is a toxin, so I wouldn't take any chances with it.

NUNLEY: Mm, not me. One of our listeners, Marlene Tosig, is waging what she calls a losing battle with horsetail at her home on Lake Winepesaukee in New Hampshire. What can she do to get rid of that?

TULLY COSTA: Well, the good news is horsetail, bottle brush, scouring rush, shavebrush, Devil's guts, or joint grass, just to name a few, can be used for polishing silver, brass, wood, or as a re-mineralizing tincture. This plant is really interesting because it's been used successfully to treat kidney, skin, and internal disorders since Roman times. Now the bad news is that this living bit of prehistoric flora is almost impossible to get rid of once it's gotten into your garden, and you know, to be honest about this, what we're fighting here is the plant equivalent of a dinosaur. Actually, horsetail predates dinosaurs by a hundred million years and it survived them. So we're looking at one of the toughest living things on this planet. This grows in the temperate zones of the northern hemisphere on the entire planet where drainage is poor and swampy and that's key to locating your garden. Now the only cure is to dig this stuff up, but even that's not a guarantee because the extensive root system is a weedy success story. The roots are slender, dark brown, hairy, creeping, and branching.

NUNLEY: Ooohh...

TULLY COSTA: Now this stuff has got to be dug out to at least an exasperating depth of 3 feet.

NUNLEY: Ow, I'm hurting already.

TULLY COSTA: Yeah, it's a back-breaking proposition. And on top of this endless underground root network, horsetail also produces fertile stems. Now you've got to cut those off the minute they come up in the spring, otherwise take advantage of the plant's high silica content, make a scrub brush with it, and use it to wash your dishes.

NUNLEY: [Laughs] Oh, my. Now that sounds most unpleasant. Have you got any resources on problem plants like horsetail that you would recommend before we close?

TULLY COSTA: Yeah, actually a really wonderful book that I came across that your listeners might want to get a copy of is Just Weeds: History, Myths, and Uses. It's put out by Chapters Publishing and of course there's always Rodale, who puts out Organic Gardening and lots of books on organic problem solving in your back yard.

NUNLEY: Meanwhile, keep those questions coming to the Green Garden Spot, care of Living on Earth, PO Box 639, Harvard Square Station, Cambridge, Massachusetts 02238. Till next time, Evelyn.

TULLY COSTA: Bye bye, Jan.

NUNLEY: Living on Earth's organic gardening commentator, Evelyn Tully Costa, runs Garden Services in Brooklyn, New York.