What Is The Use Of Perlite In Gardening?

Areas of application of perlite

Aufgepoppte Perlite lockern Pflanzenerde auf.
Popped perlite loosens plant soil.
  • Perlite as a soil conditioner in the garden: Puffed up perlites are true all-rounders in the garden. As a so-called soil additive, the rock loosens the soil and also ensures that it stores rainwater better. If you buy potting soil containing perlite, you can avoid waterlogging. If you want to work perlite directly into the soil as granules, you should use products with a grain size of 0 to 6 millimeters. If you want to use the perlite to make your own potting soil, it is best to use perlite with a grain size of 2 to 6 millimeters.
  • Perlite as an insulating material: If sustainable building is important to you, you have probably already come across insulating boards made of perlite. You can buy the rock in the form of granules or pressed boards. You can use perlite insulation boards, for example, if you want to insulate interiors, ceilings or a roof. Because perlite is not combustible, it is characterized above all by its high fire protection. Furthermore, there are, for example, bricks or mortar to which perlite is mixed.

Perlite is a virtually inexhaustible raw material that is created from volcanic rock. We’ll show you how the material is made and how you can use it.

What are perlites and how are they made?

Perlites are volcanic glasses, also known as obsidian. This volcanic glass is formed when lava with a small mass of volatile matter cools rapidly. The result of this reaction is the black and smooth rock glass known as perlite. Over time, weathering and transformation processes cause cracks to form in the rock through which water penetrates. The water carries with it various minerals that are deposited in the cracks and veins of the perlite and are later transformed into quartz, cristobalite and feldspar. In short, the black, hard obsidian transforms into the porous and loose perlite rock, which then has a rather grayish color.

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Before it can be used in garden design, for example, the perlite must be further processed, however. For this purpose, the finely ground perlite is heated in industrial plants at temperatures of up to 1000 degrees Celsius. This process ensures that the water stored in the rock expands and the perlites increase their volume by up to twenty times, i.e. they inflate. These popped perlites are white in color and somewhat resemble popcorn in shape.

Perlite – an inexhaustible raw material?

Jede vulkanische Aktivität fördert neue Perlite zu Tage.

What Is The Use Of Perlite In Gardening?

Perlite is considered an environmentally friendly alternative to peat and various building materials, enabling sustainable construction and gardening. In fact, this good reputation of the rock is justified, because every volcanic activity creates new perlite, which means that the supply of the material is virtually inexhaustible. In addition, you can usually return perlite to nature without any detours when you use it in the garden, for example.

Depending on the area of application, perlite is used as pure granules or mixed with additives. To make it water-repellent, for example, the rock is impregnated with a latex emulsion, silicone oil or a mixture of pine resin and kerosene. Even though perlite plays an important role as an environmentally friendly insulation and aggregate material, you should keep in mind that the additive kerosene is a waste product of petroleum production. Therefore, if possible, only buy perlite products that do not contain this substance or that are water-repellent without additives due to special production processes.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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