Terrain, which is to garden centers what Disney World is to playgrounds, recently hosted its 50th terrarium workshop since opening in 2008. "It is the most popular one we do," says Kedra-Maguire, who notes that the store sold every one of 300 terrariums the staff made at Christmastime.
"Terrariums are adorable," she said.
Workshops of late have been drawing more younger attendees, city-dwellers, and men. The typical gardener demographic remains middle-aged, suburban, and female, a group well represented at Terrain's most recent terrarium class.
Julie Wood of Thornton and Jane Wellbrock of Kennett Square, fellow real-estate agents and friends, remember terrariums from their childhoods.
"My granddad got us into them when I was a child," recalled Wood, who grew up in Worcestershire, England.
"Oh my God! I grew up with them as a kid. Remember the macrame planters of the 1970s?" Wellbrock said.
There's an element of nostalgia in terrarium attraction, then. But there's also something about these self-contained "glass houses" themselves, with their thick lids, sweating plants, dainty objects placed inside just so, that makes mesmerized voyeurs of us all.
Perhaps it's the draw of the small. Dollhouse furniture is a perennial favorite; dwarf varieties of plants, shrubs, and trees have become a huge hit with gardeners.
And, like snow globes and fairy scenes, terrariums project the fantasy of a mysterious, rarefied world suspended in time. We can't stop looking in there.
"When will people stop wanting to make terrariums? Never!" Kedra-Maguire said.
The first modern terrariums were the accidental invention of Nathaniel Ward, a London physician and amateur botanist whose backyard ferns kept dying, presumably from toxic fumes coming from the city's factories. It was around 1829, a time when he was also experimenting with caterpillars and moths, observing their cocoons in covered jars with a bit of soil in the bottom.
As the story goes, Ward found several ferns growing in that soil, and unlike the ones exposed to air, they were healthy. He built on this discovery, successfully planting inside the jars and dubbing his creations "fern cases." They later became known as Wardian cases or terrariums.
For the first time, sensitive tropical plants like orchids could survive transport across the seas. The cases also became a coveted fashion accessory, which, in a way, is true today.
Amy Bryant Aiello has seen intense interest "across the board" at her Portland, Ore., boutique Artemisia, which specializes in terrariums, mostly without lids. She attributes her business' success, in part, to renewed enthusiasm for the crafts of the '60s and '70s.
"It's like when I was 4, my mom made feather earrings and now feather earrings and braiding feathers into your hair are way cool," said Aiello, coauthor, with Kate Bryant, of Terrarium Craft: Create 50 Magical, Miniature Worlds, published by Timber Press in 2011.
The terrarium's draw, especially with younger people, she said, is that "everybody likes a touch of nature in the house and when you're in your 20s, you don't usually have a house and a yard and garden, and lots of money to play with in that way. Terrariums can replace that.
"And they appeal to creative people of all ages. You can make a whole terrarium based on crystals, for goodness' sake," Aiello said.
For those sticking with plants, pint-sized varieties have never been more plentiful. They include succulents, pygmy ferns, miniature palms, mosses, violets, begonias, air plants, even, for the holidays, mini-cyclamen and 4-inch poinsettias.
There are lots of interesting glass vessels out there, too, ranging from traditional bell jars or cloches to pickle jars. (Back in the day, fishbowls and hanging macrame planters were it.)
At the recent Terrain workshop, Elizabeth Horsey of Wilmington, one of four coworkers from the Partnership for the Delaware Estuary enjoying a "girls' night out," filled a turquoise blue, mason-type jar with a plant she describes as "a cute teddy bear without a head."
Horsey, who lives in a sunny apartment, thought the terrarium would help her "create outdoor space inside. And it's like something from the old world. I'm big on the Victorian time," she said.
Coworker Sari Rothrock of West Chester landscaped her "very old glass jar" with a fern and a succulent the size of a quarter. (Succulents need direct sun and are best suited to open-container terrariums, according to Kedra-Maguire.)
"The fern looks kind of old, like it's decaying a little," Rothrock said, "but this is probably one of those things you don't want to overthink."
Not to worry. "It's very, very difficult to make something ugly. I've never seen an ugly terrarium," Kedra-Maguire says.
Wellbrock, the real-estate agent with the macrame memories, was certainly pleased with her terrarium. But she couldn't stop - once home, she added a tiny Tinker Bell to it. Tinker Bell is the favorite character of her granddaughter Hannah, 31/2.
When Hannah showed up, she exclaimed, "Grandma! You have Tinker Bell in there!"
"She stared at it all afternoon," reports Wellbrock, who may unwittingly have paved the way for yet another generation's terrarium comeback.
Learn All About It
Terrarium programs in the Philadelphia region in February include:
Feb. 2: 6-7:30 p.m. at Terrain at Styer's, 914 Baltimore Pike, Glen Mills, with instructor Diane Kedra-Maguire; $25, includes instruction, potting, and decorative materials, complimentary wine or coffee. Participants can buy terrarium containers and plants at Terrain that night or bring their own vessel. Information: 610-459-2400 or www.shopterrain.com/styers
Feb. 4: 10 a.m. at Huntingdon Valley Library, 2d floor community room, 625 Red Lion Rd.; Delaware Valley Branch American Begonia Society; Ed McFarland speaks on "Growing Plants in Wardian Cases," which were the miniature glass houses used to transport exotic plants, especially orchids, from distant lands. Free. Information: email@example.com
Feb. 19: 1-3 p.m. at Terrain at Styer's. Same instructor, fee, and details as Feb. 2 program.
Feb. 25: 10-11 a.m. at Primex Garden Center, 435 W. Glenside Ave., Glenside, with Elizabeth Leo; $25, includes glass bowl, soil, and three plants. Space limited; registration required. There is a $10 fee per class due at registration. You must pay in advance. A $5 Primex gift card will be issued to each paid registrant who attends the lecture. Register in store or by calling 215-887-7500. Information: www.primexgardencenter.com.
Here are some of Diane Kedra-Maguire's thoughts on making a closed terrarium:
Choose a container that is clear glass and watertight with some kind of cover, lid, or door. There are many choices - bell jars or cloches, hanging candleholders, apothecary jars, vases, old canning jars.
Be creative, and make sure you can get your hand in there or have tongs at the ready.
Planting. Place 1/2 inch of gravel on the bottom, followed by another layer of horticultural charcoal. Fill with enough potting soil to cover the root system of your plants.
Next, the hardest part: Choose your plants. You can do more, but Kedra-Maguire believes one, two, or three work best. This gives your terrarium "negative space" in which your eye can rest.
Select plants with color, texture, and leaf size in mind.
Make a hole in the potting soil and stick the plant into it, using tongs if you have to. Water lightly. Don't overplant or crowd; leave room for growth. And be sure your terrarium top fits without crushing what's inside.
Add decorative elements - more for the "fairy garden look," fewer if you want your terrarium to have a minimalist feel.
Elements to consider include twigs, club moss, blue lichen, pebbles, balsa wood, sweet gum balls, sticks, stones, shells, and tiny pinecones.
You can also use jewelry, crystals, little candles or statues, seedpods, feathers, dried bones, colored thread, and trinkets. Personal mementos work, too.
Light and water. Place the terrarium in bright, indirect light.
Keep it moist, not wet, watering about 1/8 cup per plant, once every 1 to 2 weeks. Water at the base of the plants.
If you see some condensation inside, your terrarium is working. If you see droplets forming on the top, there's too much moisture in there.
Take the top off for a day or two and let your terrarium get some fresh air. This is a good idea even if you're not having problems.
And remember: The easiest way to kill your terrarium is by giving it too much water and not enough light.
Watch Susan Schu of Terrain at Styers describe the design elements of a terrarium at www.philly.com/ginny
Contact garden writer Virginia A. Smith at 215-854-5720 or firstname.lastname@example.org.