Those who practice the fine art of bonsai have known for years the very special qualities that professional bonsai soil imparts to soil mixes. Its unique properties help provide free passage of air and water to root systems while significantly reducing soil compaction. This unique bonsai soil is produced by expanding and vitrifying selected shale in a rotary kiln at temperatures in excess of 2000 degrees F. This process makes the soil sterile and environmentally inert. It is a natural non-toxic, highly absorbtive ceramic granule with a generally neutral PH. It is dimensionally stable and will not degrade like other amending products. There is no need for it to be re-applied year after year. A good bonsai soil profile is approximately 25% water, 25% air and 50% solid particulate matter. However, when soils are compacted, an imbalance occurs. Solid particles are pressed together, and water and air are squeezed out. With less pore space, soils become too dense for the movement of air, water and nutrients, and the favorable environment for the beneficial microbial activity necessary in a healthy growing medium, is lost. Our professional bonsai soil absorbs excess water during rain or watering, then slowly releases this excess water as the soil dries acting in effect like a time release capsule. Use as a blend with your soil mix or by itself. (Click Merchant link below for full description)