Quickscan mestverwaarding voor Groeimedia

This report explores the potential of animal manure as a renewable raw material for growing media in horticulture, in response to rising manure surpluses in the Netherlands and the growing media industry’s ambition to increase the use of renewable materials following the 2022 covenant. Commissioned by the Ministry of Agriculture, Fisheries, Food Security and Nature (LVVN), this quickscan combines literature review, data analysis, consultation with RHP and VPN (Vereniging Potgrond- en Substraatfabrikanten Nederland), and company interviews, to assess opportunities, risks and barriers. Results show that manure is abundant, especially from cattle, but its use is limited by high salt content, variability in quality and measurements, and potential contaminants. Processing steps like separation, composting, digestion, and pyrolysis can improve stability and safety, but only low mixing ratios (typically below 3% by volume) are feasible without exceeding critical thresholds. This makes the limiting factor not supply, but the maximum mixing ratio based on growing media requirements. There are also certification requirements, regulatory hurdles (e.g. related to manure processing) and quality standards. The consumer market offers the most immediate opportunities, whilst for the professional market this depends on the exact application. Unlocking any potential of manure-based products will require technological innovation to reduce salts, consistent data on product quality, certification pathways and policy adjustments to lower administrative burdens. Manurebased products can contribute to renewable growing media by providing complementary properties to other components, but only with coordination around the aforementioned barriers.