Miniature worlds under glass

Sonny Abesamis/Flickr

Sonny Abesamis/Flickr

Imagine a perfect miniature world of greenery and flowers held captive in a clear glass container like a ship in a bottle. Peer inside, and you are transported to another climate, another place -- another, more pristine, moment in time.

That’s the enchantment cast by a well-designed terrarium. After a long spell out of favor, these self-contained indoor gardens are back in vogue.

“They’re cute and precious, like pets,” says garden author Ken Druse, who tends his own “little gardens under glass” at his Sussex County, N.J. and New York City homes. “To gaze at them is as dreamy and relaxing as watching an aquarium.”

 During their height popularity in the Victorian Era, terrariums were housed in elaborate confections of leaded glass resembling small conservatories or glasshouses. They were like jewel cases, designed to protect and display choice specimens of tropical plants new to the Western World.

As Druse points out in “Planthropology” (Clarkson Potter, 2008), terrariums are decorative descendants of the entirely practical Wardian case.

During the early 19th century, plant hunters who scoured tropical South American jungles and remote Asian highlands for new species were rarely successful in bringing their rare finds back alive. After exposure to wind, salt spray and fluctuating temperatures, precious plant material often was dead on arrival.

All that changed with the invention of Dr. Nathaniel Ward, an English surgeon and amateur botanist, whose experiments in 1829 focused on enclosed mini-ecosystems. His discovery that plants could live – even thrive – in a tightly closed jar lead to the use of sealed glass containers for long-distance transport of exotic plants. These became known as Wardian cases.

Terrariums are making a comeback for thoroughly modern reasons.

“These tiny indoor gardens thrive in small apartments with imperfect light and basically take care of themselves,” Druse says. “Terrariums also solve some plant-failure problems. They are little biospheres that create their own moisture, even in dry, heated homes.”

Once assembled, a terrarium needs only minimal care since life-giving condensation keeps plants moist. Only moderately bright light is required -- direct sun can overheat and “steam” plants grown under glass.

In cool rooms, 50 degrees or so, sealed or “closed” terrariums can do well. In warmer homes these are prone to developing algae on their glass sides. One hedge against this is the use of containers that remain open, ideally those tapering to small hole at the top.

Bacteria and mold also thrive in a terrarium’s damp environment. That’s why you need to be scrupulous about using sterile soil mixes and avoiding natural wood, rocks and shells as props.

Suitable terrarium plants are those that will remain small – miniature ferns, dwarf African violets, begonias and ivies, mosses and small carnivorous plants are favorites. Water plants sparingly and only if the medium dries, and don’t fertilize. The idea is to slow plant growth, not boost it.




  • Material: Glass containers, plants, sterile potting mix, activated charcoal, fine pea gravel
  • Put a layer of fine pea gravel in the bottom of your container.
  • Mix 1 part activated charcoal, available at garden centers and nurseries, with 4 parts potting mix -- an African violet formula is ideal. Charcoal purifies the damp growing medium, keeping it “sweet.”
  • Carefully add the charcoal-potting mix to the container. A wooden spoon works well as a miniature trowel.
  • Tuck plants into potting mix and gently tamp down.
  • Water carefully, using a spray bottle and washing any soil from the sides of the container.
  • Place out of direct sunlight and monitor moisture levels. If more than ½ inch of water remains in bottom of container, you’re overwatering.


Black Jungle Terrarium Supply, 370 Avenue A, Turners Falls, MA 01376. Call (800) 268-1813 or visit

T & C Terrariums, 419 Baywood Circle, Port Orange, FL 32127. Call (386) 767-3469 or go to

Glasshouse Works, Box 97, Stewart, OH 45778. Call (800) 837-2142 or visit

*A version of this story first appeared in Inside Jersey magazine