The invention relates to a cultivation substrate (1 ) comprising one or more inner structures (5) formed of web-like or sheet-like inner material (5a) with a dry content of at least 40 wt% of natural fibres. Furthermore, the inner structures (5) of the cultivation substrate (1 ) comprise spaces and/or gaps (9), whose proportion is at least 20% of the volume of the cultivation substrate (1 ) at the equilibrium moisture content. The invention also relates to a method for manufacturing a cultivation substrate (1 ), as well as to an inner material (5a) for a cultivation substrate.
