Triple Red Line Akadama (super hard) medium grain, imported from Japan, hard fired and medium size. Used for Bonsai trees. Mix or use by itself. Akadama is one of the most popular materials used for soil mixes for bonsai trees. Akadama provides excellent drainage and aeration for healthy root growth as it porous allowing for absorption of water while spreading the nutrients inherent in its form to the bonsai trees roots.