A forthcoming perspective paper in Frontiers in Horticulture addresses the widespread but inconsistent use of the term "sustainable growing media" across the horticulture and greenhouse sectors. The publication, authored by an international group of researchers and industry experts including Dr Alexander Sentinella of Growing Media Europe, examines how the term has become diluted and proposes a more rigorous, evidence-based approach.
"The term is used to mean almost anything and everything," Dr Sentinella states. "Along with terms like 'green' or 'climate friendly', it starts to lose any helpful meaning." The authors argue that this lack of precision undermines both research comparability and informed decision-making in commercial production.
Misconceptions and oversimplification
The paper highlights a common tendency to equate sustainability with single attributes such as renewability, circularity, or the absence of peat. "People conflate sustainability with individual concepts like climate footprint or renewability, but these are not interchangeable," he explains. Labels such as "peat-free" are identified as particularly problematic, as they are often interpreted as indicators of environmental benefit without supporting data.
"'Peat-free' simply means there is no peat in the mix. It does not demonstrate lower environmental impact or improved sustainability unless this is actually measured." The authors warn that such assumptions risk misleading both growers and policymakers.
A multi-dimensional and system-dependent concept
Central to the paper is the recognition that sustainability in growing media spans three interconnected pillars: environmental, economic, and social. Environmental impacts include not only climate footprint but also land and water use. Economic sustainability involves cost, availability, and consistency, while social sustainability covers labour conditions, health, and safety.
"A product might perform well environmentally but not economically or socially. These trade-offs are unavoidable and must be acknowledged." The paper stresses that sustainability cannot be attributed to individual materials in isolation but must be assessed within the full production system.
"Growing media are part of a wider horticultural system. A substrate with a lower product footprint that reduces yield can lead to a worse overall outcome when total production impacts are considered."
© Growing Media Europe
From assumptions to measurement
To improve clarity, the authors advocate for measurable, system-based assessments. Life cycle methodologies are identified as critical tools, including environmental Life Cycle Assessment (LCA), Life Cycle Costing (LCC), and Social Life Cycle Assessment (S-LCA). The latter follows frameworks developed by United Nations Environment Programme and SETAC, enabling evaluation of impacts across workers, communities, and supply chains.
"Most conversations focus on reducing footprints, but we need to actually measure them. The results may not match expectations, which is exactly why measurement is necessary."
The paper also notes that social impacts remain underrepresented in current assessments, despite available methodologies that consider factors such as labour rights, occupational health, and community effects across the value chain.
Guidelines for responsible use of the term
Rather than proposing a universal definition, the authors outline minimum conditions for using the term "sustainable growing media" responsibly. These include explicitly defining the scope of claims, identifying which sustainability pillars are addressed, and supporting statements with verifiable data. Absolute claims are discouraged in favour of comparative, context-specific language.
"The best step forward is to use more precise terminology," Dr Sentinella advises. "If you mean lower environmental impact, then say that and measure it."
Implications for industry and policy
The findings have practical implications for growers, suppliers, and policymakers. The paper cautions against relying on proxy indicators, such as peat reduction alone, as a measure of sustainability. "If policy focuses on a single attribute, it risks overlooking broader impacts. We need to base decisions on measured outcomes across environmental, economic, and social dimensions."
The authors conclude that progress in sustainable growing media will depend less on redefining the term and more on improving how evidence is generated and communicated. "It is better to say 'more sustainable' and explain why. Clear definitions and measurable indicators are essential for meaningful progress in the greenhouse sector."
Keep an eye out for the final published paper.
For more information:
Growing Media Europa
Dr Alexander Sentinella, Co-Author
[email protected]
www.growing-media.eu
