PlantPumice.
A lightweight, porous volcanic rock that holds some water in its internal pores while adding air space and weight to a mix.
What it means for your plants
Unlike perlite it is heavier, rarely floats and does not break down. Use 3–8 mm grains at 20–50% for aroid mixes and up to 40–60% with other grit for succulents and cacti; rinse off fine dust first.
IN PRACTICE
A top-heavy snake plant stays upright in a mix with 40% pumice where a perlite blend would tip over.
Put it into practice
Perlite is light, cheap and floats; pumice is heavier, holds some water in its pores and never breaks down. Compare them for aroids, succulents and large pots.
Perlite vs. pumice: choosing the right mineral for your potting mix
