Kanuma is a volcanic pumice with a PH of approximately 5.5. It can be added to other bonsai soils to lower the overall PH or can be used on it's own. The acidity makes this a great soil for trees such as Chinese Elm, Juniper, Azalea, Gardenia and Camellias, among others. It provides good water and nutrient retention.. This is a medium grain variety, with grains between 2mm and 6mm in size. It's moisture retention properties will help greatly in preventing your trees from becoming too dry during warm weather.. Features:. Excellent water and nutrient retention. Lightweight. Adds visual appeal to any tree. Can be used alone or mixed with other soils. Visual aid to help discern when the tree needs watering