Those who practice the fine art of bonsai know the importance of quality professional bonsai soil mixes. This soils' 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. The process makes the soil sterile and environmentally inert. It is a natural non-toxic, highly absorptive 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.  This professional bonsai soil absorbs excess water during rain or watering, then slowly releases water as the soil dries, acting like a time release capsule. Use as a blend with your soil mix or by itself.