Calcined Clay is an essential bonsai material for bonsai soil mixes. Calcined or thermal treated clay helps to give bonsai soil mix proper aeration for oxygen by allowing proper spacing for roots to grow. Calcined Clay also has a added feature in that it changes color when watered, giving you a visual cue as to how dry your bonsai is. Highly recommended. Our smaller turface is ideal for smaller bonsai tree pots or evergreens.- Amount: 5 Dry Qt- Ingredients: Small Turface Calcined ClayA necessary component in proper water retention in bonsai soil. - Fills approximately a 12-14" bonsai pot.