Tillandsia are often referred to as “air plants.” They get that name because they are epiphytes, often attaching themselves to tree branches in the understory. They come in a variety of shapes and sizes, and also suited to a variety of environments. So, whatever your terrarium setup (or even your household humidity) you can find a tillandsia to meet your needs.
A general rule of thumb to keep in mind is that the thinner and harder the leaves of your tilandsia, the dryer the environment it requires. Tilandsia with wide, fleshy leaves do fine in a rainforest terrarium, but Tilandsia stricta “Hard” requires near desert conditions.
Because they are epiphytes, tilandsia do best mounted above the terrarium substrate, on a piece of driftwood or cork. Their roots are mainly an anchor, the plants receive their nutrition directly through their leaves. Tilandsia are best watered by misting heavily. The roots should be allowed to dry out between waterings to prevent rotting.
Tilandsia are part of the bromeliad family, and as such, each plant only blooms once. They reproduce through “pups” as well as by seed. Once a mother plant blooms, it will begin producing pups before slowly dying away. Some tilandsia, such as Tilandsia inonantha, grow into large clumps.
With thousands of species, hybrids, and cutivars, tilandsia offer a nearly endless opportunity to experiment with in your terrarium or greenhouse.