Horticultural Pumice Bulk

Pumice is solidified foam that forms from lava rich in gases and has cavities that create a structure that’s 70% porous and moisture absorbent. These fantastic properties make it very useful in gardening and particularly cacti growing.

Pumice is light weight and inorganic, long lasting and better for the environment than something like perlite.

Why use pumice in cactus substrate?

Horticultural pumice is useful in cactus soil because it improves drainage while still holding a little moisture inside the rock structure. That balance is especially helpful in the UK, where cactus roots need air around them and should not sit wet for long periods.

• For Trichocereus: use as part of a gritty inorganic mix to keep pots open and free draining.
• For seedlings: blend with finer grit or seed substrate rather than using large particles alone.
• For top dressing: add a clean mineral finish that helps keep the surface tidy.
• For repotting: combine with compost, grit, sand or worm castings depending on the cactus genus.

For mix ideas, see Cacti Substrate 101 and organic worm castings.