Perlite vs Pumice – Similarities and Difference Discussed

These are perhaps some of the most common natural rocks that seem to be sought-after the world over. The two are coarse and pebble-looking substances that are widely used thanks to their natural properties. The two minerals are formed as a result of a volcanic eruption. The melting and cooling process result in the formation of perlite and pumice. When evaluating perlite vs pumice it is important to note that perlite is usually subjected to heat making it expand to 20 times its initial volume.

Perlite VS Pumice

Comparing Perlite vs Pumice

Perlite is also referred to as sponge rock and must be heated to temperatures of between 1500 to 2000 degrees Fahrenheit so as to attain the required properties. The heat makes it lightweight and porous. The process begins with mining then it is crashed before being heated.

In terms of price perlite is much cheaper than pumice and is mined all over the world. It is however most abundant in the USA, a leading producer and exporter of perlite.

Perlite has a light color and is much lighter when compared to pumice. It is pure white and will float of top when mixed with soil. Upon watering it tends to spill over the edges. It is availed in various grades ranging from 2 pounds per cubic foot.

The PH of perlite is about 7 and is chemically inert. It does not have any beneficial nutrients for plants and also does not compress but rather stays as it is permanently.

Pumice on the other hand is formed due to tiny gas bubbles that are trapped inside lava prior to cooling. This ultimately results in the formation of a naturally lightweight rock. Its name pumice is derived from the Latin word “pumex”, which means foam.

Pumice is naturally porous and allows water to drain through it. It has a characteristic pale gray or dusty white color and in some instances pale yellow. Its color however depends on the minerals within the mining location.

Pumice can float in water but a little short of the much perlite does. Pumice is never processed but rather sorted by size.

Uses Perlite vs Pumice

Both perlite and pumice are used in horticulture, potting soil mixes and garden soil amendments. They both boost the garden soil drainage.  They also improve soil aeration which is ideal for optimal plant growth and sustenance.

The potted plants are prone to drainage problems and these two substances helps prevent drainage issues and also boosts moisture retention properties of the soil. This helps prevent fungal infections, lack of nutrients, and rotting. It is however much better to use perlite in potting mixes since heating helps sterilize it and hence eliminates possibilities for harmful microbes.

If your garden or potted plant thrives well in sandy soil then a better choice would be pumice since it is an excellent boost of water retention properties of the soil. As for clay soils, when considering perlite vs pumice the two are equally matched. Both will do an excellent job of boosting aeration and soil drainage in clay soils. If you have planted succulents and cactus, then the best substance is pumice since it makes it impossible to overwater plants and offers the best aeration for the plants when compared to perlite.

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