Pumice is a good soil conditioner as it is highly porous. It has excellent water and air holding capacity.

Advantages of Using Pumice
(In potting media and garden soils)

• The porous nature of pumice allows it to hold vital nutrients in the microscopic surface pores, which helps regulate fertilizer feedings. It can even be supercharged with nutrients before it is added to the growing medium.
• It has an excellent conditioner for soil that requires increased aeration and drainage. Suitable for growing cacti, bromeliads, succulents or when rooting cuttings.
• It loosens the density of heavy clay garden soils, letting in the air and water that plants need.
• It increases water retention in light and sandy soils.
• It holds moisture in the soil and reduces watering requirements. However, it will not become compact or become soggy.
• Pumice has neutral pH
• It does not attract or host fungi, nematodes, or insects.

These advantages can be realized with as little as a 10% addition of pumice to the soil or growing medium.