Exo Terra Sub StratumThe Exo Terra Sub Stratum is collected from the mineral rich foothills of the Aso Volcano in Japan. The natural volcanic soil, formed from andesitic and rhyolitic tephra, is very nutrient rich, ideal for lush plant growth in bioactive planted terrariums. The porous surface allows for excellent drainage and aeration, supporting strong root growth. The Sub Stratums friable, low density structure promotes a flourishing population of beneficial,