Fresh Ideas for Building Beauty
By Josh Coceano | Photograph by Rob Cardillo (Terrarium created by Terrain)
This open terrarium features a pink-spotted polka dot plant (Hypoestes phyllostachys).
I made my first terrarium in college, using plants grown in a semester-long propagation course, and once it was finished, I was hooked. I now have nine terrariums—the closest thing I have, as a renter, to a garden of my own—which have moved with me from apartment to apartment. Terrariums are easy to create and maintain, and they make great gifts, which can be customized by adding figurines or other ornaments meaningful to the recipient. These minigardens are also great for introducing children to the pleasures of growing and caring for plants. Any type of clear container will work for a terrarium, but glass is best, as it maintains its transparency and is easy to clean. Choose a container large enough to accommodate the necessary layers (see “From the Bottom Up”) and allow for plant growth. Bright but not direct sunlight—which can bake the plants, especially in a closed terrarium—is ideal. Whether you choose a closed system (with a lid) or an open system (like the one pictured above), keeping the plants’ roots from sitting in water is the key to success. An open terrarium will dry out more quickly than a closed one; with the latter, excess moisture can be vented by opening the lid for a short time.
From the Bottom Up
Building and Maintaining Your Terrarium
Reservoir Layer. At the bottom, sand and gravel become a sink for excess water. I start with sand, then add two kinds of gravel—a coarse layer, with water-trapping air pockets, with a band of smaller gravel on top. Choose gravel colors that complement or contrast—rather than clash—with each other and with the plants grown above them.
Soil Layer. A high-quality potting medium without white perlite filler (which will float to the surface of the container) is best. Measurements need not be exact, but a rule of thumb is that the sand, gravel, and soil should fill a quarter to a third of the container.
Plant Layer. Closed terrariums are perfect for cultivating humidity-loving tropical plants; ferns and mosses grow particularly well. Open systems need more frequent watering but allow you to grow a wider range of traditional houseplants. African violets (Saintpaulia species), for example, would do well in an open system but quickly languish in the high humidity of a closed system. See “Plants for Terrariums” for more choices.
Decorative Touches. An ornamental bark, gravel, or grit can help dress up a terrarium. Add small figurines, seashells, and other personal objects to make this minigarden truly your own.
Feeding. Dilute liquid fertilizer, about a quarter of the recommended strength, will help the plants thrive, but be aware that too much feeding will cause excessive growth and an unwanted buildup of harmful fertilizer salts.
Other Care. Pinch and prune the plants to keep them in proportion and scale to the container. Dust the container to keep it looking sharp and, more important, guarantee that light gets through to the plants.