Keep an eye on the moisture levels in the terrarium and be careful not to overwater.
Closed terrariums should be watered every two to three weeks, taking care not to wet plant leaves, which can cause damage. Keep an eye on the moisture levels in the terrarium and be careful not to overwater. Established closed terrariums may need very little water since they develop their own ecosystem. Open terrariums should be watered at least once a week, and Tillandsia (air plants) can be misted regularly.