In the older days the idea was to approximate - Loam
40 sand
40 silt [ decayed rock ]
20 clay
Then you bought your plant and put into the ground.
What we did down here, was change the particle size, try to get spheres, and used fired brick instead of decayed rock.
Also removed the clay and substituted an organic.
If you look at the various soil mixes, they tend to contain, an inorganic that holds water in itself, an inorganic that
holds water around itself and an organic that can hold onto the NPK plus micro-nutrients.
Additionally, if you use a totally inorganic, often the fertiliser is organic, plus roots rot, dust, insect poop and so on
will add back in the organic.
You can word play, compost, leaf mold, oil seed meal, humus, bark and so on, but it is an organic, that can hold
fertiliser.
The porous inorganic will hold the fertiliser in itself in the water based solution.
What really makes the difference is your attention paid when watering.
This is why they say, it takes 3 to 5 years [ if paying attention daily and thinking ] to master watering.
What you may wish to test, is the response of the expendable plant in the nursery soil, when pruned etc, and fertilised.
See if you get results you are happy with.
Good Day
Anthony
