Soils and layers
Pumice
Reusable
Light grey volcanic stone full of air. Drains and never breaks down.
What the simulation uses
- Holds water
- 27.5 % by volume
- Water it keeps after draining; the rest runs down to the drainage.
- Pore space
- 74.5 % by volume
- Room for air and water between grains; low means roots suffocate when wet.
- Weight
- 560 g/L
- How heavy a litre is.
- pH
- 6.5 to 7.5 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.
Description
Volcanic glass so full of bubbles that single pieces float. Water sits inside its pores while the gaps between grains stay airy. Being mineral, it never feeds mould.
Also called pumice stone.
Estimated, where sources were thin: bulk density varies a lot with grade; horticultural grade likely lower than ET value.