The challenge of defining "sustainable growing media": why the term is used incorrectly and what needs to be done about it

Authors: AURDAL, SIV MARI - Norwegian Institute Of Bioeconomy Research(NIBIO); SENTINELLA, ALEXANDER - Growing Media Europe; SCHMILEWSKI, GERALD - Retired Non ARS Employee; Altland, James; CARON, JEAN - Laval University; ALEXANDER, PAUL - Bulrush Horticulture; HOLTKAMP, MARTINE - Regeling Handelspotgrond (RHP); VANDECASTEELE, BART - Flanders Research Institute For Agriculture; ALANIUS, BEATRIX - Swedish University Of Agricultural Sciences

Submitted to: Frontiers in Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2026
Publication Date: 5/18/2026
Citation: Aurdal, S., Sentinella, A., Schmilewski, G., Altland, J.E., Caron, J., Alexander, P., Holtkamp, M., Vandecasteele, B., Alanius, B. 2026. The challenge of defining "sustainable growing media": why the term is used incorrectly and what needs to be done about it. Frontiers in Horticulture. 5. Article 1800902. https://doi.org/10.3389/fhort.2026.1800902.
DOI: https://doi.org/10.3389/fhort.2026.1800902

Interpretive Summary: The term “sustainable growing media” has been widely used in horticulture, but its meaning has often been unclear and inconsistently applied. Materials have frequently been labeled as sustainable based on single attributes—such as being peat-free, recycled, or renewable—without proving that they can support reliable crop production, reduce environmental impact, or remain economically viable. This lack of clarity has created confusion for growers, policymakers, and consumers, and has sometimes led to decisions that shift environmental or social burdens rather than reduce them. Sustainability is shown to depend on three pillars: environmental, economic, and social. However, these pillars are rarely considered together. Environmental claims often focus narrowly on peat reduction, while economic and social factors—such as affordability, supply reliability, and labor conditions—are overlooked. As a result, sustainability has been treated as an inherent property of materials rather than as an outcome that depends on how those materials perform in real production systems. Instead of proposing a single definition, the authors recommend minimum conditions for using the term responsibly. These include measuring actual impacts rather than assuming them, demonstrating functional and economic performance, and making trade-offs and uncertainties explicit. Claims should be framed as conditional and comparative, not absolute. Where evidence is limited, precise descriptors such as “responsibly sourced” or “quantified carbon footprint” should replace broad sustainability labels. By clarifying how sustainability should be assessed, the risk of misleading claims that undermine both environmental goals and crop production is reduced. We recommend that sustainability is treated as a system-level outcome supported by evidence, rather than as a marketing term. This approach can guide researchers, industry, and policymakers toward more credible and practical decisions, ultimately supporting the development of growing media that balance environmental responsibility with economic feasibility and social fairness.

Technical Abstract: The term “sustainable growing media” is widely used in horticultural research, policy, and industry, yet its meaning remains ambiguous, inconsistently applied, and often unsupported by evidence. Materials are frequently labelled as sustainable based on single attributes, such as being peat-free, recycled, renewable or aligned with policy priorities, without demonstrating reliable horticultural performance, economic viability, social responsibility or reduced environmental impact within real production systems. This paper examines why defining sustainable growing media has proven persistently challenging and why a single, universal definition may be neither achievable nor even useful. Drawing on existing literature and past policy initiatives, we analyse sustainability through its environmental, economic and social pillars, highlighting how narrow or assumption-based assessments obscure trade-offs and shift, rather than reduce, environmental and social burdens. We argue that sustainability in growing media is not an inherent material property but a context-dependent outcome that must be demonstrated within a defined production system. Rather than proposing a new definition, we outline minimum conditions for responsible use of the term, emphasising measurable impacts, functional performance, economic feasibility, and explicit treatment of trade-offs. Where such evidence is lacking, precise, verifiable descriptors should replace broad sustainability claims.