Terrarium Drainage Layer Calculator
Calculate the perfect drainage layer for your terrarium. Prevent root rot and keep plants healthy.
Length of the terrarium
Width of the terrarium
Height of the terrarium
How thick should the drainage layer be in a terrarium?
Rainforest terrariums need 1.5-2 inches of drainage (high water volume). Desert terrariums need 0.5-1 inch (minimal water). Temperate needs 1-1.5 inches. Small tanks (< 5 gallons) can use 1 inch minimum. Large tanks (> 20 gallons) should have 2+ inches. Rule: 1 inch per 10 gallons of tank volume, minimum 1 inch, maximum 2 inches.
What material is best for terrarium drainage?
LECA (clay pebbles) is best - lightweight, excellent drainage, won't compact. Aquarium gravel works but is heavy. Volcanic rock is good for larger tanks. Horticultural charcoal adds filtration but should be mixed with other materials. Never use regular garden soil as drainage - it compacts and causes root rot.
Do I need a separator between drainage and soil?
Yes! Use fiberglass mesh, sphagnum moss, or landscape fabric to prevent soil from washing into drainage layer. Without separator, soil clogs drainage and causes waterlogging. Sphagnum moss is natural and adds humidity. Fiberglass mesh is durable and reusable. Coffee filters work for small terrariums but degrade over time.
Can closed terrariums have drainage layers?
Yes, but they function differently. Closed terrariums recycle water through condensation, so drainage is less critical but still recommended. Use 1 inch minimum. Open terrariums need proper drainage since water doesn't recycle. Always add drainage holes to closed terrariums for emergency water removal.