"Sustainable" is used a lot in reference to growing media: on bags, in research and in policy. Often it is based on a single feature, such as being peat-free, recycled or made from renewable materials, without evidence that the product performs well for growers, is economically viable, or actually reduces environmental impact.

​

A paper by Dr. Siv Mari Aurdal, Dr. Alexander Sentinella and an international group of growing media scientists argues that the term is widely misused. Rather than proposing a new definition, it sets out minimum conditions for using the term responsibly.

​

Three pillars

• Environmental. Life cycle assessment is the most established tool, but studies on growing media production vary widely in assumptions, methods and data. Every material has environmental impacts.

• Economic. Growing media have to meet cost, availability, consistency and scale. A material that increases production risk, or needs extra inputs (like water or fertilizers) to compensate, isn't economically sustainable.

• Social. The least developed pillar: labour conditions in supply chains, worker health, and traceability.

​

​

Eight conditions for using the term

1. Consider all three pillars explicitly.

2. Say which pillar or pillars you mean.

3. Look at the whole system, not a single material.

4. Measure impacts; don't infer them from a material category. "Peat-free" is not evidence of sustainability.

5. Show that the product works and is economically viable for its intended use.

6. Make trade-offs and uncertainties explicit.

7. Avoid absolute or yes/no sustainability claims.

8. Where evidence is limited, use precise descriptions that can be checked, such as "responsibly sourced" or "carbon footprint quantified under stated assumptions".

​

Read the paper

Aurdal, S.M., Sentinella, A. et al. (2026). Why we are using the term "sustainable growing media" incorrectly and what to do about it. Frontiers in Horticulture. DOI: 10.3389/fhort.2026.1800902