Pumice: The Secret Ingredient for Thriving Plants

Are you tired of your plants getting root rot or seeming too dry or too damp? Are you struggling to find the right material to grow your cacti and succulents in? The secret is in the soil – mixing plant pumice into your soil can support your plants’ well-being and help them flourish!

What is Plant Pumice?

Plant or agricultural pumice is a natural volcanic rock used as a soil amendment. It is incredibly lightweight and porous and is excellent for a variety of uses. Agricultural pumice is made from the same material as the large stones you see in the store that are meant for exfoliation – just smaller!

What is Plant Pumice Used For?

Agricultural pumice is used as a soil amendment to set up plants for success and enhance their growth by impacting the soil. Pumice improves soil structure and loosens heavy soil because of its lightweight and porous texture. Plant pumice can keep the soil loose and airy, preventing compaction.

Pumice for plants can also improve the drainage of the soil and control water and irrigation. The texture of plant pumice lets it act like a sponge, sopping up excess water when it rains (or when you overwater your plants). Aside from holding excess water, it also releases water into the soil when it’s dry.

This water absorption trick is beneficial not only in improving the quality and water control of your soil but also in reducing unpleasant odors. Pumice for plants can absorb extra water in your compost pile or worm bin, preventing rot and lessening any bad smells.

How To Use Plant Pumice in Your Garden 

Plant pumice can be used on its own or mixed into soil or other soil amendments. For potted plants, start by mixing about one part pumice with four parts soil, increasing to a one-to-one ratio for succulents and any other plants needing more water control. The stability and drainage that pumice provides will be excellent for fostering healthy roots of beautiful plants!

You can also use pumice for plants with other soil amendments like gypsum, sand, bark, and peat moss, enhancing the drainage and moisture retention qualities of pumice even more. To supercharge your plant’s water retention, try mixing it with yucca meal! You can also use plant pumice as a soil top dressing to absorb excess water that may damage your plants.   

The benefits of soil amendments like plant pumice are numerous! Because of the absorbent, sponge-like nature of pumice for plants, it can even be used to sop up liquids like oil and grease. Simply put a layer of pumice over the spill, wait for it to soak into the stones, and sweep it up.

Can You Use Plant Pumice on its Own?

Plant pumice can be used independently without soil, particularly for semi-hydroponic plants. Learning how to grow semi-hydroponics in pumice can be an alternative to typical growth in LECA. Growing plants in pumice can be helpful, as you just need one ingredient instead of a soil mixture with other amendments!

Pumice vs. Perlite

Pumice for plants is often compared to perlite, a lightweight material made from volcanic glass. Perlite is used for many of the same reasons that pumice is; however, there are some advantages of using plant pumice over perlite:

• Stability – pumice is a more stable material than perlite and will not break down as quickly
• Weight – pumice is heavier than perlite, so not only will it weigh down top-heavy plants, but it will stay well incorporated into the soil instead of moving to the top like perlite might
• Pore size – pumice for plants has larger pore sizes than perlite typically does so that water can be more easily absorbed, and it will provide better aeration for your soil and roots
• Environment- plant pumice takes much less processing to create as it only requires breaking up and sifting, while perlite needs to be heated at ultra-high temperatures in factories

That being said, pumice for plants can be more expensive than perlite and more challenging to source. Weighing the differences between pumice and perlite is in your best interest. 

Which Plants Like Pumice? 

Different types of plants grown in all kinds of soil can benefit from agricultural pumice, including:   

• Cacti and succulents: Perhaps the most notable, cacti and succulents need excellent drainage and aeration, which is why cacti and succulent enthusiasts alike vouch for plant pumice.
• Water-sensitive plants: Many types of plants do not like to sit in pooled water. Pumice is a great tool for regulating the amount of water these more sensitive plants are getting and preventing root rot.
• Plants in sandy soils: By mixing pumice for plants into sandy soil, you can prevent water runoff and increase soil absorption and fertilization, making plants in sandy soils thrive.
• Plants in clay soils: By mixing pumice for plants into dense clay soil, you can improve the aeration and moisture balance. Your plant roots will become much healthier and have space to breathe, only absorbing the water they need. 

Plants that can benefit from pumice are not limited to the kinds listed. Adding pumice to any sort of soil mix is a great way to improve the overall health of your plants and make sure they aren’t stuck in any clogged or overly saturated soil. 

Does Pumice Degrade Over Time? 

One advantage of using pumice over other soil amendments is that it does not degrade over time. It does not decompose or compact, so it can help support the soil structure for as long as you need it.

Plant pumice will keep clay soils loose and aerated so that you do not have to add more or replace the soil with as much frequency as you would with other soil amendments. This benefit can outweigh the cheaper upfront costs of amendments like perlite because you will ultimately need to use less! 

Agricultural pumice is a soil amendment that has a plethora of uses and outstanding versatility. Getting a high-quality pumice for plants can last you for years and will be a welcome addition to your plant’s well-being.