For more than forty years, Grodan® has been a global market leader in the supply of innovative and sustainable stonewool substrate solutions for professional growers.
Stonewool is made from a natural, volcanic rock called basalt. Grodan® substrates are clean, contain no pollutants and are free of plant diseases. They also enable re-circulation of water and nutrients, so there is no waste of input materials.
The most important quality a high grade stonewool should have is uniform wetting. The stonewool should wet easily but not remain water-soaked. Good drainage is important.
At full saturation, Grodan® holds approximately 80% of its volume in water, leaving 20% of tiny air pockets. It is wrapped in UV-degradable plastic and the stonewool can be re-used in your garden to improve the aeration and water holding capacity.