Thanks to Molly for a great conversation starter regarding terrariums.
I always see vibrant green moss terrariums on etsy which are advertised as being ridiculously easy to care for etc etc. After contacting the sellers, I learned that they actually grow the moss themselves.
I know moss thrives in humid, moist conditions, and the seller lists the terrarium as being extremely low maintenance and easy to care for, but in my experience, open-air moss requires almost daily misting. Is this person just confused about the nature of these terrariums?
Terrariums can be extremely easy to care for if they are a balanced and complete system. If there is a proper water cycle and enough air circulation- an ecosystem can thrive even in a completely sealed system. When a terrarium reaches a degree of "self-sufficiency" it can be extremely easy to care for- and may need water and a quarter-turn in the sunlight only once every few months or so. However- if moss exhibits signs of dehydration or disease the system can need careful water, management and maintenance.
A healthy terrarium requires proper moisture levels- which an open container may not provide. If a terrarium container is mostly open- it would take constant humidity or moisture to keep most mosses alive. This is most easily achieved by keeping a lid on a brandy-sniffer or fishbowl shaped terrarium. A lid can be a fitted top or even something akin to a dinner plate or a piece of plexiglass.
Sphagnum or peat moss (pictured above) as available in most craft stores- as a dried but live moss. You may have seen this dried moss stuffed on top of silk plant arrangements or worse- spray painted green and advertised as "dried moss" in a terrarium. However if given proper lighting and water this craft moss will come "back to life" and will grow green and begin sprouting. You can propagate this moss yourself at home by misting it and keeping it in an incubation terrarium. If it is given a chance to really thrive- this plant becomes the almost grassy-looking moss you see in many terrariums for sale. It just takes a little patience, some creativity and some insight into what moss requires for optimum growing conditions.
Often this means high acidity, constant moisture, some degree of air circulation and a somewhat enclosed system to protect the moss from insects, mold or rotting.
Tips and How-to guides at the Fern and Mossery