@Victorim,
Our inorganic that holds water and fertiliser in solution, is 5 mm crushed earthenware red brick. It is essentially
damaged or re-crushed hollow clay building blocks.
Should take a million years to return to it's basic components.
However we found that not all trees and shrubs can handle it's high moisture holding capacity, so it blended with
5 mm silica based crushed builder's gravel.
We know about the Ball Bearing Principle and have hand rolled earthenware balls at 8 mm.
Also Leca at 10 mm approximately.
Also glass marbles at 3 mm, and in another pot/s 10 mm marbles.
The organic is aged sifted compost. Aged in a covered barrel, and kept moist, to encourage weed seeds to germinate
and die.
We did not think it made sense to go to hydroponics [ 100 % inorganic and fertiliser ] as we were not sure what effect
that would have in the tree / shrub's development x years down the road.
The earlier local use of hydroponics on tomatoes, gave fruit that collapsed structurally a day or so after harvesting.
Plus our soil though simple has worked well for 30+ years.
If you read some of the older Japanese books, you would see Akadama was used by those able to get it, the rest of
Japan used plain old decomposed Granite or Basalt or other Volcanic material called sand.
Seems to have been an extension of a farming practice over there.
We have a source of Canadian Basalt , but have chosen not to use it as our sand is Silica . Not sure if the alkali
content of Volcanic "sand" [ if any ] might harm our trees.
Hope this explains.
Good Day
Anthony
t
