Terrariums: Gardens under glass

Maureen Feighan
The Detroit News

Gray continues to be today’s “it” neutral, but as one gray day leads to another come early January in southeast Michigan, I’m craving green.

No wonder why terrariums are so refreshing. These miniature indoor gardens let you exercise your green thumb year-round while giving your space a touch of green.

And terrariums are big these days. Many local nurseries offer workshops on how to get started with terrariums – from what vessels to use to plants and care tips.

“It is gardening, but it’s also art,” says Meg Gallagher, merchandise manager for houseplants and flowering plants at English Gardens, which offers regular Make It & Take It terrarium workshops, including one on Saturday (see box for details). “It’s a definite conversation piece.”

And there are many kind of terrariums: desert ones, woodland ones, closed terrariums. Desert terrariums, often made with succulents that require little water, are very popular and easy to care for, Gallagher says.

Some of the newest terrariums are aquatic terrariums, with mini lily-pads, and carnivorous ones.

“They’re made with plants that eat live bugs” such as the Venus Fly Traps, says Gallagher. “...It’s kind of fascinating.”

Maria Colletti, a terrarium designer at The New York Botanical Garden’s Shop in the Garden and author of “Terrariums: Gardens Under Glass” (Cool Springs Press, $24.99), says a lot of people thought terrariums were going to be a “flash in the pan, but it really has taken hold.”

“Part of it is our lifestyles have sped up,” Colletti says. “Electronics have made us very busy. And it’s not only urban environments, but that’s a big part... It’s the idea of ‘I want it to be close to me, have those plants close to me.’ It’s such a pretty concept. And it’s low mainteinance – busy lives and low maintenance.”

How to get started

Gallagher says if you want to build your own terrarium, pick your container first. A terrarium doesn’t have to be in a glass container, but it needs to be transparent so the light can shine through it.

Container options abound. There are glass jars, half moon-shaped jars, square open containers, apothecary jars, lidded cookie jars, or even hanging snow globes.

Colletti says one distinctive plant can determine the design of a terrarium, shaping its style or feel.

A mixture of mosses, for example, lends itself to a tropical terrarium. An air plant terrarium is one of the easiest to create.

“The air plant is so simple to plop into any kind of glass – except for the closed; it needs air circulation,” says Colletti. “A little stones and a little sand and some decorative items, and you’re done. That’s really a very simple concept.”

Colletti says she especially likes fish bowls.

“You can easily fit your hands inside the opening of a fish bowl while working the ingredients into the vessel,” she writes. “...(And) Fish bowls can be viewed from nearly 360 degrees, from top, sides, or spun around. So when you think about your fish bowl design, decide where it will live for a time and design it for that space.”

Wardian cases are a great option for tropical terrariums. Detroit-based LeadHead Glass makes Wardian cases from reclaimed wood and glass from old local houses.

With a Wardian case, Colletti says a roof pane that swings open is important so you can release excess condensation if needed. She also suggests using bigger plants, such as palms, a weeping fig tree, or a Norfolk pine.

Pick similar plants

After picking your container, make sure you pick plants with similar watering and sun needs, says Gallagher. You can’t have one plant that likes a lot of water paired with a succulent that requires little water.

But keep texture in mind when pairing plants, she says.

“Add light colors with dark, and mix glossy leaves with textured foliage,” says Gallagher.

Succulents continue to be a hot choice for terrariums. Ivy plants are also popular, along with fittonia.

“Those come in a lot of colors, they come in pink and green and white so you have that variety,” she says.

Once you’ve picked a container and plants with similar water and sun needs, Gallagher says drainage is key. Since terrariums don’t have holes in the bottom to drain water, you have to create it.

Without drainage, “the roots will rot,” says Gallagher. “There won’t be anywhere for the water to go.”

To create your own drainage system, Gallager recommends using crushed river gravel, lava rock or any type of small stone. “You put a layer of charcoal on top of the rock,” says Gallagher. “That keeps the soil fresh and that hinders mold or bacteria. And you don’t have to use a lot of that.”

Also think about where you plan to put your terrarium, says Gallagher. That’ll determine the plants’ placement inside.

With terrariums you can view from all sides, put the largest plants in the center, she says. “If it’s only viewable from a couple sides, put plants in the back.”

Care tips

Caring for a terrarium depends on several factors: the type of terrarium and the type of plants. It may seem like a no-brainer, but don’t under-water or over-water a terrarium. And if you have a closed terrarium such as a Wardian case – which creates its own ecosystem – make sure you get high-humidity plants, such as tropical palms.

Lighting is important too, says Gallagher.

“Terrariums should never be put in direct light,” she says. “The heat off the glass will burn the plants.”

Terrariums may be low-maintenance, but they do need TLC.

“They have to be nurtured,” says Gallagher.


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Terrarium talk

English Gardens will offer a free talk on terrariums, “Terrific Terrariums,” at 1 p.m. Saturday at all of its stores. Afterward, there will be a Make It & Take It Workshop: Make A Terrarium at 2:30 p.m. It’s $19.99 which includes materials. Go to englishgardens.com/events.

Terrarium care tips

How to care for your terrarium depends on the container and types of plant you use. Below are some watering and wiping tips from author and terrarium expert Maria Colletti:

Open fish bowls: Water every other week with your spray mister on stream.

Closed fish bowls: Wipe out every week and do not water.

Apothecary jars: Keep a balanced moisture level; does not need misting.

Lidded jars: May need water every three to six months.

Cloche: Will need to be wiped out; a single plant will need water once a month.

Wardian cases: Most have a window that can be propped open temporarily.

Glass globes: Can be misted with a spray bottle on mist, not stream.