PRESS RELEASE - The environmental impact of growing media: not as black-and-white as you think
First reliable European dataset on potting soil dispels persistent myths.
When basil withers or a houseplant wilts, we often blame ourselves: not enough water, too much sunlight, or insufficient fertiliser. However, the potting soil itself also plays a crucial role; its composition and quality largely determine whether a plant thrives.
That same composition raises a less visible but important question: what is the environmental impact of growing media? Optimal plant growth requires specific properties, and the raw materials used to achieve them each carry their own environmental footprint. Peat has long been at the heart of this debate. A new study, carried out by Wageningen University & Research (WUR) and accepted for publication in the leading Journal of Cleaner Production, highlights the complexity and nuances of the issue.
For the first time, a scientifically grounded dataset has been compiled for the key raw materials used in growing media. Until now, researchers and policymakers lacked the necessary information to evaluate the environmental impact of potting soil. Consequently, conclusions were often based on fragmented data, outdated information, or even flawed assumptions. The new dataset changes this.
The study dispels the persistent myth that growing media can be made fully sustainable simply by replacing a single raw material or switching entirely to renewable resources.
Our study shows that no such ‘silver bullet’ exists. Every raw material has its own environmental impact. Jeroen Weststrate, project leader at Wageningen University & Research and co-author of the publication |
The study yields unexpected insights, particularly when the full environmental impact of raw materials (such as water use, particulate matter, nitrogen emissions, and land use) is taken into account.
“Some materials score better on climate impact, while others perform better regarding land use, resource consumption, or other environmental indicators. It is important to realise that no single raw material is free of environmental impact,” says Weststrate.
This applies not only to the most used ingredient, peat, but also to alternatives such as coconut coir, tree bark, and other frequent components of growing media. Green compost is a striking example. Because it is derived largely from recycled organic waste streams, it is often automatically viewed as a sustainable alternative. However, the results show that the full picture for compost is more complex; production methods, logistics, and choices made during the composting process all play a significant role in the ultimate environmental impact.
The quality and yield of the growing media also play a crucial role.
“There is little point in completely phasing out a raw material with a higher environmental impact if the alternative leads to reduced plant growth, and consequently higher consumption of water, nutrients, or energy during cultivation. Only by factoring in these effects and the ultimate environmental impact of the cultivated plant can measures be developed that actually result in a lower total environmental impact.” Weststrate explains.
Further research is therefore needed to provide the sector and policymakers with a scientifically grounded overview of the most effective reduction options in the coming years.
In doing so, the study offers new insights not only for the growing media industry but also for policymakers and consumers. Black-and-white solutions are rare, even when it comes to growing media. It is therefore important to take into account the full environmental impact of raw materials and their performance in practice.
Further information
Read the paper: The full study in the Journal of Cleaner Production
Background on the research: https://www.wur.nl/nl/nieuws/duurzamer-groeimedium-kijk-verder-dan-co2
About Growing Media Europe
Growing Media Europe AISBL is an international non-profit organisation representing the producers of growing media and soil improvers at European level. Coordinating its work with member companies and associations across Europe, GME provides scientific information and technical expertise on the use of growing media products, and acts as a focal point for policymakers and stakeholders inside and outside the European institutions.
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Growing Media Europe
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