Not sure this is so doable, being succulents, Sans. don't like high humidity. It tends to rot them.

That said, I know they can grow very well in the tropics as I grew up there & saw them thrive. But I suspect that required large open containers w/ excellent drainage when containerized rather than planted out in the ground, & also serious heat.

Hum, interested to see how others will respond.

Oh, but they do. Check out this gorgeous example: http://forums.gardenweb.com/discussions/2144842/sansevieri-terrarium?n=11

I just have no idea what varieties they are. Another terrarium style option is not to plant them in the bottom, but in a cup cradled by the backdrop. That way it can drain freely if need be, though really, there shouldn't be a need to water (after initially, with planting) if there's a fountain in the tank.

Have to mostly agree with Karen on this one. I live in SW Florida where it is humid 6+ months of the year, plus high temps. I have between 12 and 15 varieties of Sansevierias growing, maybe a total of 20 Sans plants. They are all in pots, mostly large and always plastic, that have large drainage holes. They are outside on the lanai and I keep an overhead fan going to move the air around. My mix is generally 1/4 (or less) C/S soil plus washed perlite, washed pumice, washed manna pro grit. They are in pretty bright light all the time.

Mine do well in heat and humidity, but I seriously guard against crown rot (have lost a number because of it). Constant moisture at the crown and/or on the roots is not a friend to Sans.

I looked at the photos in your link. That grower placed some very exotic and unusual (and valuable) Sans in a terrarium. It looked gorgeous. I wonder how it has survived since the original post. While the "environment" might be okay, in my experience, Sans can develop sizable root systems and I can't imagine 4 or 5 inches of coir and bark providing enough of a base for that. But if you decide to try it, best of luck with it. Please post photos so we can see the progress and learn from it.

I think many of the trifasciata varieties would do well in a terrarium only if they were in an extremely well drained medium, good light and good air circulation. Everything Oyster said was very accurate.

Thanks all for all the great information! I've seen several examples where very small sans were planted in a grow pot anchored diagonally in the terrarium's backdrop, thus ensuring good drainage and plenty of air flow. As I said, I'm still in the planning stages (I have the tank, but there's no rush), so I'm trying to take all of these various factors into account.

I use a fish tank for my small sans. I keep them in their pots and watch very carefully the watering. Air flow is restricted and must be careful. Mine is a long (4 ft.) 55 gal. tank. Yours would be even more air restricted. The non trifasciata varieties I think would fare much better like the example showed above. I would still keep them in their own pots with mulch placed around them. Even place a bed of gravel on the bottom to ensure of no water settling in them.

S. parva or S. doonerii