Terrariums: A great project with the kids

By Pam Baytos

OSU Extension master gardener volunteer

Terrariums are small gardens grown entirely within clear glass or plastic containers.

Almost any container will do, but those with hand-sized openings are easier to work with; small-necked bottles require the use of specialized tools.

Terrariums make a great activity with the kids.

Assembling one takes time and a steady hand, but it’s not complicated.

Select slow-growing plants with a variety of foliage shape and color, no taller than 4 inches, which thrive under similar growing conditions. A few suggestions are spiderwort, Irish moss, croton, pothos, button fern, pitcher plant, rex begonia, nerve plant, baby tears and cactus.

Decide ahead of time how the plants are to be arranged. I begin by putting a layer of gravel on the bottom, followed by a moist layer of planting medium. I use 3 parts ordinary potting soil to 1 part crushed charcoal. The charcoal is the same material used as a filter in aquariums, and it purifies soil.

There should be about 1 inch of soil in the container. To make sure it lands neatly without splattering up on the sides of the container, drop the soil through a funnel.

If the container is particularly tall, use a paper tube as an extension on the funnel.

Before setting the plants in, remove about half of the soil around their roots to make the root balls easy to manage.

To set the plants into the container I use a variety of tools, most of them borrowed from the kitchen.

For example, a wooden spoon can serve as a trowel, scooping a hole for the plant in the soil.

For holding the plants and setting them into a shallow container, a pair of kitchen tongs is perfect. Long specialized tongs are available from garden centers for deeper containers.

To firm the plants into the soil, a wine cork impaled on a long stick works well.

Then cover the soil surface with a layer of ground fir bark, which makes an attractive natural-looking floor.

Terrariums don’t require much maintenance. They need bright, but not direct light: the sun’s heat, concentrated by the glass, would boil the plants in a few minutes.

Don’t apply fertilizer. The object is to keep the plants small and healthy for years in cramped conditions.

It’s a personal choice if you cover it. With tightly fitting covers, no watering is needed, as the moisture will circulate through the container as a miniature eco-system, but the condensation along the sides make it hard to see the plants.

You can also leave the cover off and attend to their infrequent watering needs.

To learn more, go to: http://go.osu.edu/terrariums.