Closed terrariums require high amounts of light, so keep them in a bright spot but out of direct sunlight as this could cause the contents to overheat. Similarly, keep your terrarium away from radiators or other heat sources that could cause overheating.
Closed Terrariums Care
A completely enclosed terrarium requires little or no watering, but if in doubt always water less. If the soil is completely dry and the leaves are wilting this is a sign that the terrarium is too dry and needs watering. NEVER pour water into your terrarium. Water should be added a little at a time using a misting bottle to avoid overwatering as there is nowhere for excess water to go.
If your terrarium has large droplets of condensation on the glass then it has plenty of moisture and shouldn’t be watered. If this happens, remove the lid and make sure that it receives adequate light and airflow across the opening to aid drying. However, keep in mind that a balanced terrarium will have some moisture on the glass. If the terrarium glass is clear, check if your terrarium needs watering by placing your finger in the top moss layer as well as into the moss to the soil underneath. If the moss and/or soil is beginning to dry out, mist the terrarium in small doses. Larger terrarium plants can receive extra water with a spray bottle at the base of the stem to ensure water gets into the soil underneath the moss layer. N.B. you can always add more water but can’t remove it so easily!
If you see any dead or dry leaves, remove them immediately from the terrarium to avoid the unwanted spread of mould or fungus. Leaves that are pushed up against the glass of the terrarium have a tendency to get too damp and rot, so remove if possible. Plants that have overgrown the terrarium can either be pruned back or replaced. Note that plants prefer to be pruned during spring and summer months, so we don’t recommend any pruning to be carried out over winter.
What we do
We check moisture levels in our closed terrariums every 4 weeks during winter months, and check them every 2 weeks during the summer months. If there is still moisture in the system and nothing is wilting or drying out, then we hold off watering. Excess moisture is the enemy of enclosed terrariums!
As the system is enclosed, we only add a few squirts from a spray bottle at a time. We replace the lid after watering and allow the moisture to spread through the terrarium for approx 48 hours before checking it again to see whether its had enough water or needs A little more (if so repeat this process). By watering in this way, you reduce the risk of overwatering which is the main killer of enclosed systems.