Developments in alternative organic materials for growing media in soilless culture systems

There is increasing pressure on both growing media manufacturers and horticulturists to significantly reduce their reliance on peat as a constituent of substrates. This chapter distils down the available information on alternative organic materials which have emerged as the major contenders for peat dilution or replacement. We discuss materials coming from residues of manufacturing processes, for instance, wood, tree bark and coconut fibres and coir; waste and composted materials, for instance, green compost; and materials specially cultivated for use as growing media components, for instance, Sphagnum and Miscanthus. The future of growing media will be based on blends of different components which will be renewable and locally produced materials with better life cycle assessment.