Many people think of terrariums as indoor gardens, but you can make lovely enclosed gardens outdoors on shady porches. Gardeners can use the same kind of plants in outdoor terrariums as indoor terrariums, but they should always pick hardy dwarf plants and take special care of the garden. Outdoors, a terrarium should never be placed in full sun and should be watered regularly. Outdoor terrariums should always be moved indoors in winter.
New Zealand Moss
New Zealand moss, or Scleranthus uniflorus, is a hardy moss for outdoor planting that likes the brighter sunlight outdoors. This moss is low-growing with bright green grasslike leaves, and it is a spreading plant that grows outward rather than upward. New Zealand moss is hardy to U.S. Department of Agriculture plant hardiness zone 5 and can handle temperatures from 1.67 to 26.7 degrees Celsius.
French Garden Thyme
Thyme is a fragrant herb with many varieties that thrive in various conditions and hardiness zones. Thyme has succulent greyish green leaves on purplish stems. French garden thyme is low-growing and ideally suited to outdoor container gardens. This thyme variety is hardy to USDA zone 5 and prefers temperatures between 55 and 85 degrees.
Miniature English Ivy
English ivy is a common garden ivy, and the miniature variety is ideal for container gardens or outdoor terrariums. This woody vine has tiny dark green, heart-shaped leaves. The scientific name for this plant is Hedera helix, and "Spetchley" mini English ivy is a dwarf variety ideally suited to an outdoor terrarium because it can handle a wide variety of conditions. Spletchley miniature English Ivy also tolerates freezing temperatures.
Sedum, also called stone crop, is a fast-spreading, moss type plant that grows wild on rocks in mountainous regions. Sedum thrives in poor soil and can thrive even in full sun, though it will spread less quickly in shade. There are varieties with light green or variegated foliage and flowers of different colours like yellow, white and purple. Stone crop is also easy to propagate by pinching off a stem and placing in soil.
Gardeners can collect moss already growing in the garden to use in an outdoor terrarium, but they can also get bonsai mosses. Mosses that are commonly used to cover the roots of bonsai trees can be great mosses for terrariums, as long as the moisture levels are maintained. Mosses commonly used with bonsai trees include sphagnum moss, Dicrantum, Antitrichia curtipendula and Pohlia.