Terrariums make the perfect homes for specialty gardens, because you can regulate the conditions for a certain group of plants. Tropical plants require the most humidity of any group of plants, which make them the perfect companion for terrariums.
Fill the bottom of the tropical rainforest terrarium with a thin layer of small pebbles. Pebbles or rocks are usually used in terrariums to improve drainage. They serve this purpose in a tropical terrarium, but they also help increase humidity, which is crucial to the tropical ecosystem.
Add some potting mix. The tropical terrarium's potting mix must be well balanced and contain at least some peat moss and perlite. Use sterile potting mix, which can be purchased at nurseries and many garden centers.
Plant tall, upright tropical plants in the back of the terrarium. Taller plants need to go in the back so they do not block the view of shorter, ground-dwelling plants. Tall tropical plants that thrive in terrariums include bromeliads, dieffenbachia, calathea, palms and croton.
Choose a few smaller tropical plants for the front of the terrarium. The best choices are pothos and phildendron because these plants will spread around the bottom of the terrarium and create a forest floor.
Put a tarantula in your tropical rainforest terrarium. Many animals eat plants, and some may simply add too much work to an otherwise low-maintenance terrarium. However, tarantulas make the perfect terrarium pet, because they only feed on decaying plant material and harmful insects. They also have a tropical look, adding to your motif.
Consider a few accents for the tropical terrarium. Add rocks, a small sandy beach or a battery-operated fountain.
Place the tropical terrarium in bright but filtered light. Direct sunlight makes temperatures inside the terrarium too hot, but most tropical plants thrive in bright conditions. If placing directly in front of a window, filter the light with a transparent curtain.