When it comes to tending to house plants, I’ve been known to have a brown thumb. I’ve even managed to kill an aloe plant in the past, which is nearly impossible to do. Fortunately, there’s a way for non-green thumbs like me to connect with the plant world in a way that requires very little maintenance, or so I learned this afternoon at a DIY Terrariums class at my local library.

Terrariums are miniature, self-contained eco-systems constructed inside a glass container with a lid. As I learned today, the concept of a terrarium dates back to an accidental discovery by a London physician in 1827. While Dr. Ward was experimenting with cocoons in covered jars, he found tiny plants growing in the jar’s soil. Upon further experimentation, we was successfully able to grow ferns in covered containers, and the concept eventually grew in popularity.

Terrariums are relatively cheap to make, with most materials available at local garden stores (and a few items also likely available at neighborhood dollar stores).  You’ll need a glass container with a lid or cover, small stones or gravel, activated charcoal (a special kind bought at a gardening store, not the kind from your fireplace), sphagnum moss (aka green moss), sterile potting mix and several tiny plants (no more than 2 inches tall). In our class, we used glass vases, and I added a plastic lid from a coffee canister when I got home. It’s a temporary fix until I can cut a piece of cork to fit my container.

The terrarium is constructed in layers with 1/2″ stones or gravel, 1/2″ activated charcoal, a thin layer of moss, 5 sprays of water from a spray bottle,  2″ of soil, 2 or 3 plants of your choice, another 10-15 sprays of water, and optional embellishments such as statues or ornaments (I chose a seashell to add to mine). The photo below shows the ideal set-up for your mini eco-system (class handout courtesy of Melissa Richmond).

In terms of plant selection, it depends on whether you would like to create a tropical or a woodland environment. Tropical terrariums are ideal for indoor temperatures in the low 70s, and popular plants include creeping figs, small ferns, fittonia (aka nerve plant), peperomia, and spider plant. Woodland terrariums are ideal for indoor temperatures in the mid- to upper 60s, and common plants include seedling evergreens, wild strawberry, small ferns, and impatiens.

In our class we made tropical terrariums. I thought this was fitting since today marked the first day of snow in the Portland metro area. For my environment, I chose spider plant, red fittonia and some bright green moss.

A few other tips we learned in class include:

• Do not place the terrarium in direct sunlight. It is better to keep it in moderate, indirect light. I am placing mine on my cookbook shelf in my dining room, about 5 feet away from a window.
• Ideally, plants in closed terrariums water themselves. Moisture in the plants creates condensation, which runs down the sides of the container into the soil. If you have too much moisture in your container, remove the lid for an hour or two to allow some of the water to evaporate. If there is no condensation, add a little more water with a spray bottle or turkey baster.
• As your terrarium matures, remove dead leaves or spent flowers with tweezers or chopsticks in order to maintain a healthy environment.
• If plants are growing too big for the container, they may be pruned with a pair of scissors.
• For more information on terrariums, visit http://gardenersnet.com/hplants/terrarium.htm.