By Kim Foley MacKinnon

As winter approaches, a terrarium, generally defined as a glass or plastic container used for growing plants indoors, is a wonderful way to keep a little green in your life as well as a creative way to keep kids engaged with nature.

I asked two avid terrarium builders for advice in getting started. Faith Salter, mother of two and director of volunteer relations at the Appalachian Mountain Club, has been making terrariums since she was a child and now shares her passion with her two kids, ages 6 and 10. Tovah Martin, author of The New Terrarium, among other books, also started building terrariums when she was a child. At one point she had 22 in her house!

“There's something about terrariums that just appeals to kids,” said Martin. “It’s the wonder of minutiae, it’s the illusion of magic, and it’s the draw of the surreal. Kids relate to the smallness of it.”

Salter agrees. She learned how to make terrariums from her grandmother and calls them “magical miniature verdant worlds preserved under glass.”

“Looking for the tiny plants and mosses that make up the terrarium requires close inspection of the small things underfoot—the kinds of plants and lichens that many people simply pass by or step on,” Salter said. “Building terrariums puts those humble wee plants on center stage and gives kids a chance to marvel at them.” 

One of the great things about terrariums is that they can be built very inexpensively. Salter’s grandmother picked up cool jars and glass containers at yard sales to use in her creations. In Martin’s book, she describes making terrariums with everything from fish bowls to canning jars to vases, items you may already have in your home.

“Here’s a work of art that your kid can whip up without spending a fortune on supplies,” said Martin. “With a few forays into the woods, a child can return home with all the fixings for his or her fantasy terrarium.”

It’s also a wonderful way to build memories.

“My son Owen said it was like having a piece of the forest right on our table,” Salter said.

Salter sent me her step-by-step guide (see below) to building a terrarium and Martin’s book (and website) is full of tips.

Step-by-step guide to building a terrarium 

Step 1. You need a vase, a jar, or some other clear container, ideally one where the opening at the top is large enough for hands to get in and arrange the garden.

Step 2. Bring a small trowel and head out with a few buckets looking for plants and other interesting things like birch bark or rocks that will add texture and interest. It’s good to choose a collecting place that is not right on a hiking trail so that people don’t have to see the impacts. There are always interesting small growing things among rock formations. Encourage the kids to collect the small plants with their roots and dirt intact, including the mosses. Wintergreen adds beautiful color accents, but be careful not to disturb the berries, which bruise easily. Princess pine takes on forest-like proportions when set against smaller samples in the container.

Step 3. Collect some coarse sand or fine gravel and place it in the bottom of the jar for drainage. Then set to work arranging your collections. It’s sometimes hard for kids to understand that small-scale plants look big when they are set against nothing but mosses. Salter’s grandmother used to buy her tiny toy animals like deer and bears so she could pretend that she had created a massive fern forest or mossy plain. Martin reminds adults to teach kids what not to pick up, like birds’ nests and poison ivy.

Step 4. Once kids have created their landscape, spritz the plants with water as needed. Avoid overwatering! Terrariums are like small greenhouses, trapping moisture inside and there’s no set timetable for watering. You’ll need to check to see if the soil is moist or not and water accordingly. 

Step 5. Cover the terrarium with plastic wrap and tie with a ribbon or string if it doesn’t have a top. It’s a good idea to punch a few holes in the plastic or lid to allow for air circulation.

Step 6. Healthy terrariums can keep their green for ages. Salter said that the ones she made with her children lasted weeks until the family returned the plants to their native habitat. Her kids enjoyed the idea that they had brought them in for enjoyment, then released them back to the wild.

What To Know

Collecting plants, even in small quantities, impacts the environment. To minimize this, follow a few simple guidelines:

• Collect in your own yard, a friend’s yard, on school grounds, or on another private property where you can obtain permission.
• Do not collect on public lands. Collecting in national forests, national parks, or other public lands violates Leave No Trace principles. If in doubt, check land managers’ websites to see if they allow foraging.
• Collect close to home— transporting plants can spread invasive species. In some cases, it’s illegal to carry invasive plants across state lines.
• Collect small quantities, and only collect from areas where you can leave plenty of the plant growing.
• Return still-living plants to their original locations once you’ve had a chance to enjoy the terrarium.

Learn More

Tovah Martin has written about terrariums on her blog. She also offers classes and workshops throughout New England about building terrariums and other gardening topics. Visit her website for details.