Calcined Clay

Calcined Clay is a baked clay that does a great job at holding water so that your Bonsai won’t dry out throughout the day and also acts as an acidifier. Calcined Clay is the American version of the Japanese Akadama.
 

-2 quarts Bag

Reference: 1 bag fills up an empty 10x8x3in pot. 

- 20 quarts bag

Covers about 1 cubic foot.