Closed terrariums are very self sustaining and only need to be watered a few times a year. The key is to establish a proper moist level. To do this, the condensation level needs to be monitored. Do not over water. Too much misting or watering will do more harm than good.

Keep a close watch for the first 4 weeks after the build.

Inside the glass, the water cycle is happening and if water levels are correct, condensation should form on one side of the terrarium about once a day. If no condensation forms on the inside of the terrarium, add a couple of tablespoons of water a day until it does.

If heavy condensation stays throughout the day, it is a sign of over watering. Heavy condensation looks like water streaking down the sides of the glass or a fog so thick, your plants aren’t very visible. If you are finding signs of overwatering, leave it open for a few days to let the excess water evaporate and wipe up excess condensation on the glass, using a paper
towel.

Once a good moisture level is achieved, avoid opening the terrarium too often. Frequent
opening can result in moisture loss and destabilization of the ecosystem.

Do not expose terrarium to direct sunlight. The sunlight will cook the plants inside. They need indirect light. Near a window is ideal, but no so close that the sun is touching it. Keep your terrarium indoors, as higher temps will kill your plant.

Periodic maintenance is important to keep the terrarium healthy. Clean the inside of the glass with a paper towel and trim any overgrown plants. Remove any dead plants immediately. Mist or lightly water your terrarium when you no longer see any condensation at all on the glass all day long. An established terrarium will only need to be watered every 2-3 months.