Pumice is a lightweight volcanic rock which is very porous. Its density is less than that of water, which means that this stone floats in water. It is created when a volcanic eruption exposes the lava to gas-rich substances such as water vapour and carbon dioxide. This gravel is therefore chemically identical to lava and, depending on the volcanic eruption, has a light to dark colouring.  


The raw material is mined in Germany near Koblenz, in the Laacher See area. In the so-called Neuwieder Becken, the content is stored under a thick layer of topsoil. This material dates back to the eruption of the Laacher Lake volcano about 12,900 years ago. The most powerful volcanic eruption in recent earth history in Central Europe ejected approx. 6.5 km³ of volcanic material. During the outbreak, several eruption columns rose to 30 kilometres in height and led to falling deposits of pumice, also called "fallout" or ash. Over several months this led to layers of sediment over 15 meters thick.


iNTERBiMS GmbH has access to the most extensive pumice deposits with the best quality spectrum in the Eifel region. All qualities are available in all common delivery forms, from raw material from the pit to washed material. At INTERBIMS you can buy different stone sizes or grain sizes, both in big bags or loose.


iNTERBiMS GmbH has special, stationary screening and crushing plants with which the material can be screened in best quality.

The products are, e.g. suitable for gardening and landscaping, for green roofs as well as for plant substrates, lawn substrates or tree substrates.

Field of Application

  • The basis for substrates in gardening, landscaping and Green Roofs
  • As an essential substrate base for plant substrates for soil improvement, suitable for lawn substrates and tree substrates
  • The substrate improves aeration, water storage capacity and is the lightest natural raw material in horticulture.
  • For green roofs due to its high water storage capacity and low weight
  • For the production of pumice materials with an excellent thermal insulation capacity
  • As filter material in water treatment
  • In the manufacture of jeans to create the "stone-washed" effect
  • As an abrasive, e.g. wood or silver rings or for foot care for sanding off calluses

Product Description

Pumice offers many positive functions in the garden, not only for professionals. The substrate can be used mainly to improve the quality of soils and is an essential component for growing media. Due to its open-pored structure, the substrate ensures proper aeration of the ground, water is stored, and the soil texture is optimised overall. It promotes root growth and nutrient supply. 


The substrate is ideally suited as a mineral aggregate for plant substrates which are characterised by a low density. Pumice is natural to mix and optimises all soils that need to be loosened up, such as loamy or clayey soils. Soils that are often subject to waterlogging are enhanced by adding pumice substrate. It improves the pore structure and causes aeration of the ground. Washed material is also frequently used in cactus soils, as an additive for citrus plant soils or palm soils and in rockeries.

Features Sifted Pumice (SP)

Graining Bulk density

0-4/5 SP

ca.  950 kg/m³

    0-4 SP

ca.  880 kg/m³

  0-12 SP

ca.  850 kg/m³

    4-8 SP

ca.  780 kg/m³

  8-16 SP

ca.  780 kg/m³

Features Washed Pumice (WP)

Graining Bulk density

 0,5-2 WP

approx. 680 kg/m³

 0,5-8 WP

approx.  670 kg/m³

 4-8  WP

approx.  620 kg/m³

 8-16 WP

approx.  600 kg/m³

Delivery Form

iNTERBiMS offers individual products in all common delivery forms:

 ✓   Truck 

 ✓   Big Bag at 1.00 m³ / 1.50 m³

 ✓   Bag of 25 litres / 40 litres

 ✓   Silo truck

Substrates Application

Pumice is the starting point for our substrate mixtures with, e.g. lava and zeolite. Here we provide all substrate mixtures based on natural material or washed material, which we use in our substrates for plant substrates, as well as for roof substrates for green roofs, lawn substrates and tree substrates.


Smaller grain sizes (0-8 mm) are mostly used for soil improvement for horticulture. Larger grain sizes (8-16mm) are more suitable as drainage substrate for hydroponics, raised beds or as a substrate for succulent and cactus soils.