Vertical, hydroponic gardens - good for the air and for design

The Philadelphia Inquirer (MCT) - Debbie Cox often jokes that she has the best seat in the house.

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As receptionist in the 11-month-old West Grove, Pa., corporate headquarters for Dansko, the footwear firm, she has a clear view of the giant green wall with lilting waterfall that dominates the 2 ˝-story atrium.

"It's very relaxing," Cox says of the 20-by-22-foot wall, which is tufted with tropical plants and bathed in natural light.

Dansko's green wall is technically called a biofilter or biowall. Plants grown hydroponically _ without soil _ remove carbon dioxide and volatile organic chemicals from the air, filter them through bare roots, and, using beneficial microbes, break them down into benign components. The filtered air returns to the building's fresh-air system.

That's a lot of fancy talk for a relatively new technology that enlists plants to clean the air. And what's prettier _ a frilly wall-jungle or industrial ductwork?

"I'm happy to come to work now," Cox says.

Dansko's biofilter, one of fewer than a dozen in the United States, is a sophisticated example of a broad concept known as vertical gardening. The idea was glamorized in France by Patrick Blanc; now, it's growing in Canada and catching on here.

There are as many names as uses, both indoors and outside. Whether called green or living walls, biowalls, indoor-air or botanical biofilters, they can improve air quality, add an edgy design element, function as an unorthodox food or flower garden _ or all of the above.

Ed Snodgrass, whose Emory Knoll Farms in Street, Md., grows plants for green roofs and walls, thinks the current emphasis on sustainability will fuel greater interest in Dansko-style biowalls. "I think they're wonderful, because there's a whole lot of nasty stuff inside buildings that these things take out," says Snodgrass, author of "Green Roof Plants: A Resource and Planting Guide" (Timber Press, 2006) with his wife, Lucie.

Snodgrass grows vining cucumbers on a large "vegetative retaining wall" he built at the farm. It's perfect for would-be gardeners with limited space or creaky knees, and can easily be adapted by homeowners, businesses, and municipalities to control storm-water runoff. That's already being done in Vancouver, British Columbia; Portland, Ore.; San Francisco; and St. Louis.

"The EPA (Environmental Protection Agency) has been after people for storm water for the last 20 years," Snodgrass says. "They're kind of running out of patience, so as these technologies get recognized, retaining walls will be a lot more common."

Some have taken the vertical concept, quite literally, to uncommon new heights with talk of converting city skyscrapers to "sky farms" that grow crops and raise fish, chickens, and pigs.

But most examples are closer to earth.

Noise barriers along the southbound Blue Route approaching Swarthmore were planted with decorative and sound-absorbing succulents and grasses after creeping junipers folded in the heat.

Drexel University has plans for a four-story, Dansko-like biowall in the atrium of a $60 million Integrated Sciences Building to be built this fall at 33rd and Chestnut Streets in Philadelphia. Donna Murasko, dean of Drexel's College of Arts and Sciences, was inspired by a three-story version designed by biowall innovator Alan Darlington at the University of Guelph in Ontario.

"It's amazing. You walk into this typical university building, and it's just absolute calm that you get," says Murasko, who hopes to fill the Darlington-designed Drexel wall with native plants. She also wants to enlist students to scientifically measure the wall's effects.

This fall, too, Longwood Gardens in Kennett Square, Pa., expects to break ground _ underground, actually _ on some elegant, domed restrooms. They'll radiate off a glass-topped corridor lined by a decorative green wall that may be dotted with orchids.

And Suzann St. Marie, a nurse from Northeast Philadelphia, is building a deck with green wall off her soon-to-be renovated rowhouse kitchen. She has discovered organic food, loves to cook, and wants to grow basil, lemon thyme, mint, parsley, and sage.

"I thought that would just look wonderful out there and give me a little oasis," says St. Marie, who learned about green walls last month at the Go Green Expo in Center City.

Visitors to this year's Philadelphia Flower Show were treated to a low-tech green wall designed by five Temple University Ambler students. They built a wooden frame with 2x4s, screwed four-inch potted plants to the frame, rigged up an irrigation hose and small drip tray, and misted the plants as they dried out during the weeklong, Italian-themed show.

Lisa Falls, a junior studying landscape architecture, helped grow the silver lace, lemon button and Boston ferns, Labrador violets, ivies, and spider plants for the exhibit, designed as a modern, softer interpretation of the Italian Renaissance-era stone terraces.

"I think it's a great way for city gardeners to use the space they have. It's beautiful to look at, and a lot of the same plants _ annuals, herbs, vegetables _ that grow in your yard will grow up the wall," says Falls, who is thinking of planting a green wall on her boyfriend's city patio this summer.

For a permanent outside wall, Falls recommends buying pressure-treated wood or plastic modules to prevent rotting, a ready-made irrigation system, and water-hoarding succulents such as sedums and sempervivums.

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How about lettuce?

Last year, McDonald's planted lettuce seeds to spell out fresh salads on a Chicago billboard as a promotion. "Pretty wacky," says T.J. Daniels, of Bright Green Technologies in Detroit, which supplied the "living wall" panels.

And last summer, some Los Angeles homeless shelters installed "edible crop walls" to grow fruit and vegetables for residents, a program that has been copied elsewhere.

So there are many ways to go, depending on imagination and budget. Biofilters such as Dansko's, designed by Furbish Co., of Brooklyn, Md., can cost up to $200 a square foot of wall elevation. Maintenance, too, is a consideration: Murasko says the 70-by-20-foot Drexel wall could require $1,000 a month.

The water needs nutrients, plants need checking for vermin and aphids, and even green walls have been known to develop yellow and brown spots.

"Like anything else," Snodgrass says, "almost all these green technologies have a return on investment. But initially, they're more expensive."

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FOR INFORMATION

Here are some Web sites where you can find information on green walls:

http://www.brightgreenlivingwalls.com/

http://www.furbishco.com/

http://greenroofplants.com/

http://phillygreenwall.com/

http://www.urbanfarming.org/

http://www.verticalfarm.com/

http://www.nedlaw.ca

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© 2009, The Philadelphia Inquirer.