Akadama - Traditional bonsai soil

Akadama has been used for centuries in Japan as the soil of choice for bonsai horticulturists.  The word akadama means "red ball soil".  It is a granular clay of volcanic origin that is dug from pits.  It is then dried and sieve separated into various sizes.  After the separating process is completed the soil is then fired in kilns to remove any organic material.  Thus this medium is very stable and relatively inert.  It is generally pH neutral making it a great material for growing almost any plant because the pH can be manipulated according to the species requirements.  Akadama can be used by itself or as part of a special mix.

There is very little 'dust' or loose particulates in akadama and for this reason it doesn't appear to be a very good potting medium compared to the familiar western mixes of sand, compost, soil and peat.  Nothing could be further from the truth as akadama has the wonderful property so necessary to bonsai plants and trees...it drains well yet unlike sand or pebbles it retains moisture and nutrients in its tiny pores and crevices.  The drainage in combination with its unique quality of moisture retention allows the root system to absorb nutrients and water more efficiently promoting abundant and healthy growth.  The constant replenishment of fresh water and fertilizer also prevents molds, fungus and disease from occurring.  Another forgotten requirement of a plant's root system is the free passage of air.  If a soil is used that compacts and becomes dense, air is the first element that is removed creating an imbalance.  This imbalance does not allow the root's proper nutrient transfer and death will soon occur.  The correct mix of air, water and nutrients are especially important to a container bound plant.

Akadama soil is also very pleasing to the eye.  The 'grounds' around the bonsai are easily kept neat and clean by sweeping.   Any unwanted intruders such as weeds or grasses can be removed quickly and without disturbing the the roots of the bonsai as would be the case if a heavy soil were used.  It has a great longevity and does not need to be replaced since it does not decompose.  It is much easier to repot a specimen that is rooted in akadama since it does not compact.  This makes for a much less traumatic transition for the plant or tree.

Akadama has been part of the bonsai culture for generations.  The soil is as integral as the plants and trees that thrive in it.