photograph: Spike mafford / Vaughn Bell

Seattle artist Vaughn Bell is bringing a big terrarium to Expo Chicago—along some a lot of little ones you can take home.

Thousands of mini earth-and-moss terrariums will be available for adoption this weekend at the Expo Chicago art fair on Navy Pier. The caveat: aspiring terrarium adopters must sign adoption paperwork that promises lifelong care of the moss microcosms.

If you fail to nurture and maintain your terrarium, Seattle-based artist Vaughn Bell says the guilt will wholly be your own. Bell herself hopes that the lesson of her “Pocket Biospheres” translates to the bigger picture of individual responsibility to environmental issues.

The project is sponsored by the Natural Resources Defense Council, which also participated in last year’s Expo with “Garbage Wall” by artist Gordon Matta-Clark. “There’s a deep history of activism in the art world, and in the environmental world,” says Elizabeth Corr, the NRDC’s manager of art partnerships. “We don’t often get to look at that overlap,” she says.

If you’re not ready to jump the gun and sign the adoption contract, Expo visitors can stick their heads into “Metropolis,” a five-by-five foot terrarium full of hang plants also designed by Bell. It’s an “intimate worm’s eye view of the landscape,” says Bell, who stocked the terrarium with native Midwestern plants, including wild prairie grasses, ferns, and wild ginger. (I told Bell about the “stinky onion” etymology of Chicago, which seemed to intrigue her. At press time, no stinky onions have been integrated into the terrarium.)

“One of the surprising aspects is how powerful the smell is,” says Bell of her immersive terrarium. “The art fair, like most art venues, is a pretty sterile environment,” says Bell, so moving from “the air-conditioned space to smelling the earth is transformative.”

Vaughn Bell’s NRDC artworks are on view through September 22 at Expo on Navy Pier. expochicago.com.

More: Here's the Casual Art Fan's Guide to Expo Chicago.