Most houseplants are suitable to grow in a terrarium. Plants that are small or grow slowly are the best choice. Choose plants that make a landscape under glass. To give a terrarium more interest, choose plants that have different heights, colors and shapes. Take into consideration the requirements of each plant. Never plant a cactus with palms and ferns because the water requirements are very different. All plants in a terrarium need to have the same water and sun needs.
Plant the taller plants at the back of the terrarium so that they will not shade smaller plants. These plants can grow up to the top of the terrarium but should be replaced once they start to bend in closed terrariums or grow outside an open terrarium. Good tall plants include some ferns like asparagus fern and smaller palms. Prayer plants give some interest and color with multicolored leaves. Cryptanthus has starlike leaves in a variety of colors from olive to pink and red. There are even dark purple and multicolor varieties. Crotons grow tall and lend gold and maroon shades to the terrarium.
Plant mid-size plants around the interior of the terrarium. Several begonia varieties do very well and have leaves in green, bronze and silver. Begonia imperialis has a metallic shine and white flowers. Peperomia grows in a medium-size clump with leaves that are green to silver with white or pink veins. They also produce pom-pom blossoms. Dwarf African violets are a suitable mid-size plant, although some are very small. The leaves are delightfully fuzzy and flowers bloom in white, blue, purple, red and pink.
Smaller plants need to be at the front of the terrarium so that the sun can shine on them. Some of the dwarf African violets are only a few inches high. Irish moss is a low-growing plant that creates a carpet of green throughout the terrarium. Other varieties of mosses are suitable for terrarium growing as well.
Plant creepers in the corner of a terrarium or near the rear. Swedish ivy will grow up the walls of the terrarium and will need to be clipped back every once in a while. Pilea or creeping Charlie wanders along the base of the terrarium with green, bronze or silver leaves. Creeping fig and philodendron will also wind their way about a terrarium.