Moss needs adequate moister in order to endure and grow. When that need is not fulfilled the moss dries up and goes dormant until the conditions are right again for it to awake. 

 

The blue drum is 1/2 filled with water. Inside the drum also lies an ultrasonic generator, emitting ultrasonic frequencies that gradually but ultimately transforms water into mist. 

 

The mist then accumulates in the drum. The fan atop the lid of the drum pulls air in from the room, into the drum, forcing the mist out of the drilled holes circling the lid. 

 

The mist is then projected upward in an attempt to sustain the moisture viable for the moss to flourish.