I don't know how it could turn out "disastrous." I would take a tiny portion of the moss, place it in your terrarium, and see what happens.

For terrarium conditons, I would reccomend high light, a slighy acidic soil, and high humidity.

Hey foxy! Fancy meeting you here! I don't see how putting the moss in your terrarium could hurt. It obviously likes the conditions (temps, etc.) of your home, so you probably have a better chance of success with this moss in your terrarium that you would with wild-collected moss (which often needs a dormancy period in these northern climates). I wish I had moss growing on my houseplants. . . even on just the pots!

Thank you both!

Sahoyaref- I have been peeking in here and have been thinking about building a terrarium for a while now. I have to tell you your pictures have been a major inspiration. I can't wait to see what you come up with for your new one:)

Foxy.