I am upgrading aquariums and plan to turn my 3 gallon aquarium into a terrarium. The tank has no openings once the top is on, so it's a perfectly moist enviroment for tropical plants. Currently, I have a very young polka-dot plant that I'll keep in the tank until it outgrows it. However, I'm also on the lookout for plants that won't outgrow the tank, or at least not for a very long time. I'm not finding much info on non-flowering (which I truthfully prefer) plants that remain small. Does anyone here have any suggestions? P.S., this tank is a hotbox, which is why I'm taking it down, so warm-weather plants would be perfect. Thank you for any feedback.

No, this tank doesn't come with a heater, but it constantly stays around 77+degrees no matter what the room temp is, which is why I refer to it as a hotbox. I was under the impression that fittonia actually grew larger than the polka-dots, but I will look into smaller varieties of those, as well. I suppose I can find moss by just walking outside, and ivy is pretty easy to find, as well. Thanks for the tips :)

Since I seem to be having trouble finding generiads, selaginellas, or sinningias, (aside from african violets) can anyone recommend a place where I can buy seed(lings) of these plants? TIA.