Charcoal

From BonsaiWIKI

Horticultural charcoal is a porous carbon, used as a natural filter to help absorb impurities that could be toxic to roots and to improve soil drainage

Typical application rates vary. The manufacturer recommendation is around 1 tablespoonful in the average size bonsai pot


Bonsai Soil Components
Inorganics: Shale | Sand | Haydite | Turface | Ceramis | Oil-Dri | Decomposed Granite | Kitty litter
Volcanic: Pumice | Perlite | Vermiculite | Lava
Japanese Soils: Kanuma | Akadama | Hyuga
Organics: Fir bark | Redwood bark | Peat Moss | Coir | Muck | Charcoal | Compost | Field soil | Potting soil