Soils and layers

Zeolite

Pale porous mineral grains that soak up ammonia. A filter layer.

What the simulation uses

Holds water: 30 % by volume; Water it keeps after draining; the rest runs down to the drainage.
Pore space: 50 % by volume; Room for air and water between grains; low means roots suffocate when wet.
Weight: 900 g/L; How heavy a litre is.
pH: 7 to 8 pH; How acid it keeps the soil.
Mould risk: none; How much fresh food it gives white mould; high-risk soils fuzz over in the first weeks.
Nutrients: low; Plant food it brings.
Presses down to: 97 % of its loose depth; How far pressing can pack it, keeping its weight.

Porous volcanic grains used much like charcoal. Besides ammonia, they hold water and never break down. Lay them below the soil.

Also called clinoptilolite.

Estimated, where sources were thin: values estimated from hobby and horticultural references; not measured.