I have lots of air plants (Tillandsia) and I would like to place them in a closed terrarium. Will this type of plant survive the type of humidity and moisture that comes with a closed terrarium environment?
And can I just place this plant in some sand or can I place it in soil as well?
The reason I ask is because I'd like to place the air plant alongside some ferns inside the terrarium. Hence, if I could just place both plants on the same soil bed, it will be very convenient.
In a word, no. The natural environment of these plants is high in trees where there is good air circulation and bright diffuse light. Humidity and moisture requirements vary by species but air circulation is essential.
In a terrarium they will get not get air circulation but they will get a constant level of higher humidity which will promote rot.
I have maintained these plants quite successfully in a more open terrarium where these was a lot of light from High Pressure Sodium lamps and good air circulation. They were attached with silicon to cork. Maintenance was to mist them down with distilled or filtered water once a day
I am by no means an expert but I have successfully been growing several varieties in a closed terrarium (not sealed as I do open the lid about twice a month to apply some orachid food). I have had the set up for about two years and have had them flower and put off successful pups. The container is a several gallon glass container from Wal-Mart (kitchen section). The glass lid fits quite well so there is negligible moisture loss. The bottom is filled with larg-ish aquarium stones. I space them quite well apart and don't have them resting on their bases. The terrarium sits in an East facing windowsill. As with all closed terrariums the most difficult factor is the moisture level. The rough estimate I use is that the terrarium should be without significant condensations for a few hours a day. From what I have read the thinner leaved ones are from more naturally humid environments so I would experiment with those, however I have several varieties. Good luck, maybe it's just luck for me but I really enjoy this terrarium and think it's worth an attempt if you're interested.