Water Cycles in Terrariums

I found a great explanation of the water cycle in a closed terrarium by Oscar at arizona-plants.com.

The water cycle in a terrarium is very similar to the process that occurs in nature. The evidence of this continuous cycle can be seen in several ways. In a properly constructed terrarium enclosure, moisture will appear as condensation on the inner surfaces of the enclosure. Gravity will cause the condensed moisture to run back down to the soil. Moisture also will condensate on the surface of the plants in a process referred to as canopy interception...

Part of the terrarium water cycle involves the plants through the process of transpiration where water is expelled from the plant. Continuing the cycle, the water expelled from plant cell evaporates, condenses and precipitates all in the confines of your terrarium.

arizona-plants.com