Fill a small bucket of water with fresh, de-chlorinated freshwater and soak the pillow moss for five to 10 minutes.
Place the pillow moss in a terrarium so that the soil is facing toward the bottom of the tank and the green foliage of the moss is facing upward. Pillow moss generally comes in compacted clumps, and you may need to pry the moss apart after it has soaked in order to cover the base of the terrarium.
Mist the moss several times each day to maintain a high level of humidity in the terrarium. Space the misting times out through the day so that the pillow moss has a chance to completely dry out in between.
Adjust the florescent light so that the moss receives 10 to 12 hours of light each day and ensure that the temperatures in the terrarium remain above 65 degrees. Install a heating pad to maintain the temperature, if needed.