The new terrariums: mini-worlds fashioned big

Remember those old elementary-school terrariums — lidded aquariums filled with plants or plastic soda bottles growing science projects?

Today's aquariums are chic and rule-busting, popping up in interior design and gardening stores. They now include many different materials and plants. In fact, today's miniature worlds under glass can be simple still lifes — no living parts need participate.

That's some kind of easy.

"There's a little maintenance to it, but it's very, very low maintenance," says Amy Bryant Aiello, who owns a terrarium shop, Artemisia, with her husband, Michael Aiello, in Portland, Ore. She also wrote a book, "Terrarium Craft" (Timber Press, 2011), that includes how-to steps for building a beautiful and long-lasting terrarium, and 50 projects for inspiration. She uses materials including mosses and lichen, quartz crystals, river rocks, seashells, glass pebbles and driftwood.

"The idea is to play with the materials and enjoy the process itself," Aiello says in her introduction.

More examples of grownup terrariums are presented in Tovah Martin's book "The New Terrarium" (Clarkson Potter, 2009).

A well-planted terrarium can thrive for many years, provided you have the right materials and location.

Some plants, such as ferns, prefer bright, indirect light, whereas a succulent, such as cactus, prefers a stronger, direct light. Air plants, which don't root in soil and are handily watered — with a good soaking every week or two — do well in terrariums, Aiello says. Houseplants in 2- to 4-inch pots work best.

Instead of the traditional layering of rock, charcoal and soil in a terrarium, Aiello uses high-quality sand. Depending on the plant, she may use some soil to help it get established. Otherwise, she leans toward the many-colored, sterile sands, often layered with pebbles or shells, for their visual impact through clear glass.

Her favorite sands are garnet, which is reddish-purple; hematite, which is black; pure quartz, which is creamy-white; and Monterey beach sand, which is tan in color.

Beach and play sands are a no-no in a terrarium, says Aiello, because they're not sterile. "Dirty" sand must be washed, screened and kiln-dried to be safe for plants. The Monterey beach sand, often used in fish aquariums, is available this way.

Kathie Helmericks has been making terrariums for about a year, and they now fill the tabletops and shelves of her Fort Collins, Colo., home. She recently started a business, Glass Garden Terrariums, and sells her verdant creations in small Denver shops, including Ironwood Collection and Moondance Botanicals.