This European Standard specifies an instrumental method for the routine determination of electrical conductivity in a water extract of a soil improver or growing medium. The determination is carried out to obtain an indication of the content of water soluble electrolytes in either soil improvers or growing media. This method is not applicable to liming materials and preformed materials such as mineral wool slabs and foam slabs. NOTE The requirements of the standard may differ from the national legal requirements for the declaration of the products concerned.