The Water absorption of 4 Bonsai Soil Types
This is a test report on the water absorption capacity of 4 common bonsai soil types. The tested soil types are; Akadama, Kiryu, Kanuma & Seramis.
Short Description of soil types
Akadama:
Akadama is type of red clay imported from Japan. It comes in several qualities, fired and unfired. The unfired variety can absorb more water, but will break down quicker in the soil. Used in the experiment was a hard double-brand Akadama type.
Kiriyu:
Kiriyu is a hard volcanic soil with a high lime content, also imported from Japan
Kanuma:
Kanuma is a yellow soft volcanic soil with a high acidity, usually used for acid-loving plants like Azaleas.
Seramis:
Seramis is a brick-orange high-fired clay granulate, with a high water retention capacity, which will not break down in the soil over time.
Testsetup
Initially all soils have been sifted to get an even granular size for all types.
Removed were all particles smaller than the small size standard bonsai sieve, and all particles larger than the medium size standard bonsai sieve.
In a secondary experiment I sieved both the bag of Kiriyu as well as the bag of Kanuma in four different sizes. Fines, 1-2mm, 2-4mm, >4mm. Here are two pictures of the Resulting proportions in granular sizes.
All four soil types have been dried in the oven at 100C for several hours to remove any remaining traces of retained water.
A volume of 200ml was measured out from each soil and each batch was weighed.
Once everything was weighed another 200ml of water were added to each batch.
Everything was left standing for 60 minutes, and than the water was drained from each batch with a kitchen sieve in the order in which water was added to them. Finally all batches were weighed a second time, and the difference between the two measurements was calculated.
Measured Results
Akadama:
Dry: 140gr
Wet: 215gr
Diff: 75gr
Kiriyu:
Dry: 150gr
Wet: 200gr
Diff: 50gr
Kanuma:
Dry: 50gr
Wet: 140gr
Diff: 90gr
Seramis:
Dry: 75gr
Wet: 135gr
Diff: 60gr
Margin of error: +/- 5gr.
Additional Observations
The Akadama seemed to soak up the water immediately and none remained floating, while the Kiriyu still had some floating paritcles after an hour. Both the Kanuma and the Seramis had a substantial amount of floating particles throughout the hour the were left soaking. Stiring did not improve the situation.