Pumice and Perlite: What are the key differences and benefits? A not so definitive guide.

Last Updated: January 17, 2023

Pumice and perlite are both commonly used soil amendments that are added to potting mixes to improve drainage and aeration. Both materials are lightweight, porous, and can help prevent soil compaction, making them ideal for use with succulent plants, which require well-draining soil to thrive. However, there are a few key differences between pumice and perlite that you should consider when deciding which material to use for your succulents.

What’s the difference between Pumice and Perlite?

Perlite is processed and expanded to make it lighter than pumice.

Pumice is a naturally occurring volcanic rock that is formed when lava cools and solidifies quickly, creating a porous, sponge-like structure. Pumice is highly porous, with up to 80% of its volume consisting of air-filled pores, which makes it an effective soil amendment for improving drainage and aeration. Pumice is also relatively lightweight, making it easy to mix into potting soil.

Perlite, on the other hand, is a naturally occurring, glassy volcanic rock that is formed when lava cools and solidifies slowly, creating a structure that is similar to pumice but with smaller pores. Perlite is highly porous, with up to 90% of its volume consisting of air-filled pores, which makes it an effective soil amendment for improving drainage and aeration. Unlike pumice, perlite is processed and expanded by heating it to high temperatures, which causes it to puff up and become lightweight and crumbly.

Which is better for my succulent plants, Pumice or Perlite?

It comes down to personal preference.

When deciding which material to use for your succulent plants, it’s important to keep in mind that pumice is a naturally occurring volcanic rock, while perlite is a processed and expanded form of volcanic rock. Pumice has larger pores than perlite, with up to 80% of its volume consisting of air-filled pores, while perlite has smaller pores, with up to 90% of its volume consisting of air-filled pores. Pumice is relatively lightweight and easy to mix into potting soil, while perlite is even lighter and more crumbly, making it easier to work with but more prone to dust and mess.

Overall, both pumice and perlite are effective soil amendments for improving drainage and aeration in potting soil. Pumice may be a better choice for heavier soils, while perlite may be a better choice for lighter soils. Pumice and perlite materials are widely available at garden centers and online, and can be mixed into potting soil at a ratio of at least 25% by volume to improve drainage and aeration. The choice between pumice and perlite ultimately comes down to personal preference and the specific needs of your succulent plants. I use Kellogg soil as a base and typically add pumice over perlite since there’s already perlite in the pre-made soil mix.