Closed terrariums are fully enclosed glass containers whereas open terrariums are mostly enclosed with an open top or side wall.
Closed terrariums are fully enclosed glass containers whereas open terrariums are mostly enclosed with an open top or side wall. In a closed terrarium without airflow, the air is recycled and the forced humid environment acts as a mini ecosystem that does not require additional water once it's established. Open terrariums receive fresh air to reduce humidity.