The search for alternative growing media constituents fuels the need for terms and definitions for biological characteristics of growing media and gold standard methods

Growing media are commonly evaluated with respect to their physical and chemical properties and some standard methods were established during the 1990s (CEN methods). Biological characterization of growing media has not received the same attention over the years. Currently, there is a search for alternative growing media constituents to replace peat. A cascading use of valorized material from societal side streams is considered. This development engages expertise from various disciplines who often neither own a common terminology for biological factors and processes in growing media, nor a common set of methods to describe them. This hampers the comparability between various studies as well as properties and qualities of different products. This opinion note highlights factors to be considered for biological characterization of growing media and sets up a disposition for the establishment of a common terminology.