The Rain Forest substrate regulates the terrarium's humidity in a natural way by absorbing and slowly releasing moisture. Its hygroscopic properties is maximised by adding natural sphagnum moss to the mixture. Adequate air humidity levels aid in shedding and help prevent respiratory infections. The unique size and shape of the bark particles, in combination with natural sphagnum moss, allow frequent irrigation of your plants while still providing good aeration for healthy root growth. Exo Terra Rain Forest is heat-treated to reduce bacterial contamination.