How a terrarium is built, layer by layer
5 min read
Drainage
A layer of clean gravel or clay pebbles at the bottom gives excess water somewhere to go, so roots do not sit in it.
Barrier
A thin mesh or sheet of landscape fabric stops soil washing into the drainage layer.
Activated charcoal
A thin dusting keeps the water sweet and slows mould. It is not a substitute for drainage or airflow.
Soil
A mix suited to the plants: a peaty, airy mix for tropicals, a gritty mix for succulents.
Plants, then hardscape, then moss
Plants are set first, wood and stone arranged around them, and moss pressed in last to cover bare soil.