All vivariums are terrariums, but not all terrariums are vivariums. This tongue-twister adequately sums up the conundrum facing hobbyists searching for information about the creation of terrariums. A terrarium can refer to a glass enclosure containing just plants, just animals or both plants and animals. A vivarium contains only plants. Creating a plant-only terrarium, or vivarium, can provide you with a miniature ecosystem to observe and enjoy day in and day out. Hone your green thumb and improve your decor with a simple terrarium that takes little effort to set up and minimal effort to maintain.
Decide what look you would like to achieve with your terrarium. Consider the elements that you want included -- plants, decorations, soil. Figure out what aesthetic you would like your project to embody -- elegant, kitschy, simple or elaborate.
Place a layer of sand in the bottom of your aquarium. About an inch is sufficient for a 30-gallon aquarium. Layer another inch of gravel or pebbles above the sand.
Add a layer of activated charcoal. This is easily obtainable from aquarium and pet supply stores, and keeps the air within the terrarium fresh when the lid is on.
Separate the sphagnum moss with your fingers until it is light and fluffy in texture. Cover the layer of gravel with a layer of sphagnum moss. This completes the filtration needed to keep water from stagnating in the soil to prevent root rot and overwatering.
Fill the aquarium with a thick layer of potting soil. The soil does not need to be any particular type. Pack the soil firmly, but no so firm that it is hard to move.
Arrange the plants you chose within the terrarium. Play around with different layouts until the plants are pleasing to your eye.
Add decorations or ornaments. Use your imagination to envision a scene around your plants. Would a castle and small dolls be appropriate? What about a wildlife scene with deer and a few fake trees?
Add the hood-style lid to your terrarium. Hood-style lids have a spot for a light bulb, allowing you to supply your terrarium with light to grow.
Place a low-wattage grow light into the hood of your aquarium. Metal halide lighting is excellent for plants that do not receive natural light, while high-pressure sodium lighting can supplement natural lighting. Choose the lowest wattage available, preferably 100 watts or below.