Frequently Asked Questions

Stone wool is a mineral wool made of volcanic rock. Stone wool consists of 5% solid material in the form of stone fibres. The remaining 95% is made up of pores.

The basic materials for our stone wool are basalt and limestone. These are melted to form lava in an oven with a temperature of 1,500°C. The lava is then poured over a number of fast-rotating discs. Thanks to the centrifugal force, the drops fly off the discs and lengthen to form fibres. The process can be compared with candy floss being made at a fair. The fibres are then compressed to form a sturdy mass, from which the slabs and blocks are then cut.

Our stone wool growing media are designed for Precision Growing in a greenhouse. Precision Growing focuses on ‘root zone management’, or in other words, steering of the root environment. Everything that happens in the stone wool substrate has an impact on the functioning of the root environment and therefore the development of the plant. So, we continually investigate how our products, tools and user advice can respond perfectly to changing circumstances, so that the plant is given the very best care, without wasting resources. Learn more at introduction to growing on stone wool.

With inert we mean that stone wool growing media after production is pathogen-free and does not bind or buffer anything. It is not completely inert in a chemical sense, suggesting that it doesn’t react with anything.