Bioactive volcanic substrate. The Exo Terra Sub Stratum comes from the mineral-rich foothills of Mount Aso in Japan. The natural volcanic soil, formed from andesitic and rhyolitic ash, is very rich in nutrients, ideal for vigorous plant growth in bioactive planted terrariums.

The porous surface provides excellent drainage and aeration, promoting strong root development. The crumbly, low-density structure of the Sub Stratum encourages a thriving population of beneficial, nitrifying bacteria, creating a self-sustaining, living ecosystem in the terrarium.

The active, beneficial bacteria in the soil will break down biological waste, keeping the terrarium clean and healthy.