The BioDudes handcrafted bioactive substrate for terrestrial reptiles such as Monitors, Snakes, tortoises, and other burrowing species. This substrate is specifically designed for biomes that can get quite hot, but have minor humidity spikes throughout the day. Not only does the Terra Firma not need a drainage layer, its design allows for proper water retention while holding all burrows and tunnels your critter creates! Terra Firma provides excellent organic nutrition for your vivarium by creating necessary air pockets for root development and plant health. These air pockets are also necessary for the springtails and isopods to create a sustainable population in the vivarium. 

There is no drainage layer needed with the Terra Firma.