Life cycle assessment of growing media: a baseline dataset for European horticulture

Growing media underpin a substantial and growing share of European food and ornamental production, with 116 million cubic metres used globally per year. Their environmental footprint has become a focus of regulatory and commercial attention, but comparative assessments to date have been fragmented in scope and rely on outdated data, limiting their value for research and industry. This study presents a Life Cycle Assessment of twelve constituents and thirty mixes (covering seven applications) representative of European horticulture. The study follows a cradle-to-gate scope, including use-phase emissions for all organic materials. Climate change impact and single score (weighted impact of 16 categories) are presented per functional unit (1 m 3 ) at the constituent and mix levels. Wood fibre (15 kg CO 2 eq/m 3 ) and expanded perlite (33 kg CO 2 eq/m 3 ) had the lowest climate change impact; white peat (219 kg CO 2 eq/m 3 ), green compost (249 kg CO 2 eq/m 3 ), and black peat (390 kg CO 2 eq/m 3 ) had the highest. Single score results show a reversal in ranking for white peat (7.7 mPt/m 3 ) and coir constituents (9.0 to 10.5 mPt/m 3 ), emphasising the need for multi-indicator assessments to minimise the risk of shifting environmental burdens. Green compost presents a high climate change impact and single score result (21.3 mPt/m 3 ), but substantial uncertainty of this estimate highlights the need for further inventory data improvement. Mix-level results indicate that substantial carbon savings can be achieved by strategic formulation of mixes in the sectors of fruiting vegetables, potted plants and ornamentals, and tree nurseries. Assessment at the application level is identified as the next methodological priority to define strategies for efficient use of growing media resources.