ASHS 2015 Annual Conference

In France, and more largely in Europe, the main constituent of growing media used in soilless culture are peats, due to their physical qualities (water retention, aeration, physical stability). But, this fossil carbon resource is non-renewable (in our lifetime due to slow growth habit of peats) and societal demand and ecological policies are demanding a more wise use of peat and peatlands (Stategy for Responsible Peatland Management, IPS, 2010; EPAGMA Code of Practice for Responsible Peat Management, 2011). There is also increased interest in promoting renewable organic materials (bark, coir, wood, compost). Commission II (Horticultural Use of Peat) of the International Peat Society conducted a survey in order to evaluate the amounts of growing media constituents used in major growing media producer countries in the EU. This survey was continued in more detail in France for several years by the C.A.S. This survey asked for amounts of organic, composted, mineral and synthetic constituents in horticultural substrates, and a split between professional and retail markets for all constituents used. Data show that there is an increase in the use of composted organic material in some countries, in particular for the hobby sector. Synthetic materials are of no importance in EU growing media. Due to the specific properties of mineral materials, these are often applied in professional media. The availability and price of organic materials other than peat, i.e. bark or coir, often determine if a material is used as a constituent or not. Bog peat is still the overall predominant growing medium constituent in the EU. Peat-free growing media are highly esteemed by some stakeholder and user groups but still play an overall minor role in industrial production of growing media.