Akadama Japanese Pumice 14L. (Popular for Bonsai, Cacti, Succulents and other plants)
Akadama is, in fact, a form of volcanic soil (Pumice) mined exclusively in Japan and has excellent properties for plant growth. Akadama is light in weight and therefore easier for pot handling, but most importantly, they have the following beneficial properties:
Akadama is, in fact, a form of volcanic soil (Pumice) mined exclusively in Japan and has excellent properties for plant growth.
- Drains perfectly if prepared correctly (see below).
- Allows air to be drawn into the mix when watered.
- Maintains near-perfect moisture retention for plant health.
- They are granular in character and aid in root and nebari development.
- Allows greater control over fertilisers in the potting medium.
Akadama is Neutral in PH, so it is very safe to use on all plant types.
The Akadama used for bonsai potting purposes in Australia is HARD Akadama, and comes in 4 grades or grain sizes:
Size Guide:
Super Small Akadama 2-4mm – 14L Bag (Used mainly for cuttings and more miniature bonsai, such as Shohin and Mame.)
Small Akadama 2-6mm – 14L Bag (for use in most-sized pots and trees)
Medium Akadama 6-12mm – 14L Bag ( for larger trees and pots)
Large Akadama 12-21mm – 14L Bag (Used mainly for drainage layers in larger pots)
More Information:
In using Akadama, it is advised to follow the repotting system recommended by all Japanese Bonsai Masters and Growers:
The first (bottom) layer is to use the large-grade of Akadama (for drainage). Then a 50/50 mix of medium and fine grade (depending on the size of your Bonsai) for the remainder of the pot. If this is adopted, the resulting growth, particularly in the second year after repotting, is strong yet controllable.
The Super Fine Grades of Akadama and Kanuma can be used for cuttings, either combined with various other components in a 50/50 mix with River or Propagating Sand, or used straight out of the bag. I like to use a blend of components in my trees, Equa.
IMPORTANT NOTE:
Akadama can be reused several times, making them very economical (gently sieve them each time, removing dust and water accordingly).
With Kanuma: After repotting, the pot should be watered copiously until the water runs out clear from the bottom of the pot. This ensures very little residue will form at the bottom of the bonsai pot.
SOIL: MIXES:
In Japan, it rains for the month of June (Northern hemisphere) and the temperature is about 30°C; July is around 35°C with about 99% humidity. These mixes have been very effective in Japan for approximately 100 years and, when used correctly, yield excellent results.
We recommend experimenting with different mixes to determine the best growing medium for your specific growing conditions and environment.
HARD AKADAMA (neutral pH):
Used for Coniferous, deciduous and all other varieties, except acid-loving plants.
Black Pine/White Pine/Shimpaku: Akadama 7 parts, Coarse River Sand (CRS) 3 parts.
Red Pine: (1) Akadama 6 parts, CRS 2 parts, Japanese Black Soil or Coco Peat 2 parts. (Ordinary peat repels water if it dries out in the mix.)
Or:
(2) Akadama 8 parts, CRS 2 parts.
Zelkova/Elms: Akadama 8 parts, CRS 2 parts.
Maples: Akadama 8 parts, Sphagnum Moss 1 part, CRS 1 part.
Ficus: 100% Akadama.
Australian Natives: This is currently an open field but Akadama has been used 100% on its own, mixed with Kanuma and/or Pumice and other media with remarkably good effect. Very strong healthy growth and good flower production have been recorded to date.
NOTES:
Sphagnum Moss should be prepared by drying and then rubbing it through a medium sieve to create even particles before adding it to the mix.
If using River or Propagating Sand, sieve out the finest particles. Small gravel of a uniform/graded size could be used instead.
When repotting, avoid jabbing too hard with the chopstick, as this can break down the granules. Once the potting medium has been lightly jabbed with chopsticks, tap all sides of the pot to encourage further settling of the potting medium.
Large particles produce heavy root and heavy top growth, while fine particles produce fine roots and fine top growth - important for pines in particular and any bonsai once the basic structure is established.
Following these simple instructions, a perfect, well-draining, and open mix can be achieved, ideal for bonsai culture.