Soils and layers
LECA (expanded clay)
Reusable
Light, round clay balls that drain and never break down. The usual drainage layer.
What the simulation uses
- Holds water
- 14 % by volume
- Water it keeps after draining; the rest runs down to the drainage.
- Pore space
- 80 % by volume
- Room for air and water between grains; low means roots suffocate when wet.
- Weight
- 380 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
- none
- Plant food it brings.
- Presses down to
- 97 % of its loose depth
- How far pressing can pack it, keeping its weight.
Description
Clay fired at about 1200 °C puffs up into these pellets, which stay near neutral pH. They wick water upward, keeping the jar humid. Lay mesh on top so soil cannot wash down, and rinse them to reuse.
Also called Hydroton, clay balls, hydroballs, expanded clay aggregate.
Estimated, where sources were thin: water_holding_pct_by_vol and air_filled_porosity_pct not from a datasheet; porosity split (inter vs intra-particle) estimated.