A moss terrarium is an ideal way to bring a touch of nature indoors. It is also a good way to add interest to a low-light environment, coffee table or office cubicle. Moss terrariums aren't difficult to plant and are easy enough for young children to master with very little adult assistance. Once planted, moss terrariums require only an occasional drink of water to remain green and lush.
Place about 1 inch of pebbles in the bottom of a glass container with a lid. Use both large and small pebbles. Scrub the pebbles under clear water first to be sure they are free of bacteria and insects.
Put a layer of moistened peat-based commercial potting mixture over the top of the pebbles. Use as much potting mixture as you like to make the moss terrarium visually appealing, but don't use less than 1/2 inch.
Gather moss for the moss terrarium. Look in cool, shady corners of your yard or on brick walls or building foundations. Remove the moss with a trowel or a table knife. Store the moss in a plastic bag until you're ready to plant it. If necessary, trim the moss with scissors so it will conform to the shape of the glass container.
Press the moss lightly into the soil in the glass container. Spray the moss lightly with a plant mister. Water as needed to keep the moss moist, usually about once every month.
Place a decorative stone in the moss terrarium for added interest. Add decorative elements such as small glass, plastic or ceramic sculptures or figurines, if desired.
Place the lid on the glass container. If you notice condensation building up inside the container, remove the lid or place it at an angle to allow more air circulation. Place the moss terrarium in indirect light.