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Closed vs Open Terrariums

The single most important decision when planning your build.

CLOSED

Closed Terrarium

  • ✓ High humidity, self-regulating water cycle
  • ✓ Ideal for tropical ferns, mosses, fittonia, peperomia
  • ✓ Lower maintenance once established
  • ✓ Beautiful condensation effects
  • ✕ Can overheat or grow mould if too wet
  • ✕ Not suitable for succulents or cacti
Best for: Tropical plants
OPEN

Open Terrarium

  • ✓ Good airflow, lower risk of mould
  • ✓ Works for succulents, cacti, air plants, some carnivores
  • ✓ Easier to access for pruning & maintenance
  • ✓ Can be more decorative
  • ✕ Dries out faster — needs more frequent watering
  • ✕ Higher light and humidity management required
Best for: Arid & semi-arid plants

Quick decision guide

High humidity tropicals + low maintenance desired? → Closed
Want succulents or live in a bright dry room? → Open
First terrarium ever? → Start closed (more forgiving once balanced)
Want to display on a sunny windowsill? → Open or use very careful closed
Many people start with closed and later experiment with open or hybrid “open top” designs.