RYUUSEN (DRAGON SPRING) PREMIXED PROFESSIONAL BONSAI SOIL (MEDIUM) 13.5 LITERS PREMIXED BONSAI SOIL (MEDIUM) 60% of heat-treated Akadama 25% of heat-treated pumice, 10% of Kiryu, and 5% of Fuji-sand SIZE 3.0 TO 6.0 MM PRODUCT WILL BE SHIPPED USPS PRIORITY MAIL BOX 13.5 LITERS Akadama ( Akadamatsuchi, red ball earth) is a naturally occurring, granular clay-like mineral that is used as soil for bonsai trees and other container-grown plants. It is surface mined, immediately sifted and bagged, and supplied in various grades: the deeper mined grade being somewhat harder and more useful in horticulture than the more shallow mined grades.