The steps in making a terrarium are fairly simple (see the steps at right): choose a glass container, fill it with an inch of gravel/glass for drainage, an inch of charcoal to prevent mold and an inch of clean potting soil (gravel/sand for cacti). Choose plants with the same light and water needs, and start putting them in, adding rocks and other sculptural materials and filling in with more soil to anchor tall things. Spray with water and place in good, but not direct sunlight (or they’ll fry).
That’s the easy part. But the fun part is making your terrarium quirky, special or just plain weird – and keeping it alive. Here are some tips from the experts:
• Search quirky places for unusual containers: thrift and salvage stores, garage sales, hardware stores, your own cupboards or basement. Think outside the box.
• When it comes to plants, think unusual. Texture, shape, size, color and attitude all help create a terrarium vibe. Aim for contrast.
• Search the same places for unusual sculptural items: porcelain dolls, bones, crystals or other objects, says Lisa Kinoshita. Scour beaches for rocks, shells and driftwood.
• But don’t scour your garden, says Sue Goetz. It’s worth paying for a small quantity of new gravel and soil, even florist’s moss, to avoid bringing unwanted critters, eggs or disease into your terrarium. “You give them a warm environment at 70 degrees and you’ll hatch everything,” Goetz says wryly.
• Remember that an almost-closed terrarium will create its own humid environment. You may not need to water much, and you definitely shouldn’t use plants like succulents that like it dry. Try ferns, moss or airplants instead.
• Keep it tidy. Find or make long, thin tools that will let you plant, pull, prune and rearrange. Goetz sells a few long-handled clippers and widgers (weeding tools), but she also likes long-handled tweezers (from hardware stores). A wine cork on the end of a skewer will help tamp down soil; a butter knife will help you move it around.
• Finally, if things die, they die, says Kinoshita. Put them on the compost heap and try again.
Which plants for which container?
Closed (or nearly, like a bell jar, lantern or small-mouthed sphere): ferns, moss, lichen, violets, airplants, bromeliads, miniature orchids, ivy, impatiens, primrose, miniature begonias.
Open-mouthed (like a vase, goblet or big bowl): Succulents, cacti. Plant them in sandy soil (or, for airplants, just place them on glass rocks or sand) and don’t water.
Avoid altogether: Herbs, alpine or rock garden plants.