The water in a terrarium can build up dissolved solids and ought to be drained or the water replaced with fresh water occasionally. Also, it's easy to keep things too wet in a terrarium, especially an undrained one. In addition, the lack of moving air can cause a buildup of pathogens and promote fungal growth. And moreover, terrariums (especially mostly enclosed ones) can build up too much heat in direct sunlight, turning into a solar oven and baking the plants.
Any of these factors, including root and crown rot from being constantly too wet, fungal buildup and infection from being too wet for too long and having poor air circulation, or from being too wet and too cool at the same time for too long, overheating from solar gain inside the container, can cause a decline in a plant's health that may lead to death.
My own personal guidelines:
- Moist, not wet
- Plenty of light
- Fresh, moving air
- No terrarium or high-sided container, unless growing strictly inside under artificial light.
Anyway, sorry to hear about the loss, and better luck next time. We've probably all killed our fair share of plants, poor things.
Steve
!!!
The plants in the terra died ,I don't know why.I just came back from hoiliday and all turned black....