In a recent study published in the Journal of Environmental Management, researchers Nymphmary Daphne J. Santiago, Holger Braun, Benedikt Rilling, Carsten Herbes, and Terese E. Venus explored the shifting landscape of the circular bioeconomy. Their investigation centered on how hobby gardeners in Germany make decisions when faced with alternatives to peat, a traditional but carbon-intensive component of potting soil. Because potting soil is often viewed as a low-involvement product, consumers frequently rely on mental shortcuts or heuristics rather than conducting deep research into every ingredient. The researchers sought to understand how these shortcuts, particularly those related to where a product comes from, influence purchasing behavior and the overall success of environmental policy goals.

The findings revealed a powerful bias toward regionality that often overrides other sustainability data. When consumers were aware of the origin of their potting soil components, they demonstrated a significant preference for materials sourced within Europe. This was particularly evident in their willingness to pay more for biochar, which was the most valued alternative in the study. Interestingly, while biogas digestate also saw an increase in acceptance, biochar remained the clear favorite among target consumers. This regional preference serves as a double-edged sword, as it provides a clear marketing path for European biochar producers but creates a significant hurdle for high-performing sustainable materials that must be imported from outside the continent.

Quantitative results from the experiment showed that providing origin information caused a dramatic shift in consumer valuation. For instance, the preference for cocopeat turned from positive to negative once its non-European origin was disclosed, resulting in a significant drop in its perceived utility. Conversely, the willingness to pay for biochar increased significantly when its European origin was highlighted. This suggests that for many consumers, the perceived environmental benefit of local production is a more persuasive factor than the technical lifecycle assessment of the material itself.

Beyond origin, the study highlighted the effectiveness of specific sustainability signals. Gardeners reacted positively to labels claiming specific percentage reductions in carbon dioxide emissions and to the presence of the HORTICERT certification logo. These visual cues provided a sense of security and transparency, though they were still secondary to the choice of the peat alternative itself, such as biochar. The research also found that while gardeners generally believe they understand the quality of the soil they buy, their ratings for peat and its substitutes were remarkably similar. This indicates a lack of technical knowledge regarding the horticultural characteristics of peat, which presents an opportunity for educators to better explain how to use alternatives like biochar effectively.

The study concluded that for a peat-free transition to succeed, stakeholders must navigate these complex consumer heuristics. Industry players are encouraged to use regional labeling as a primary strategy for local biochar while finding new ways to communicate the sustainability of imported goods without triggering negative biases. Policymakers can support this transition by fostering credible, standardized certification schemes that help consumers move beyond simple shortcuts. By aligning marketing strategies with the deeply held values of gardeners, the horticultural industry can more effectively move toward a future that protects vital peatland ecosystems while meeting the practical needs of home growers.

Source: Santiago, N. D. J., Braun, H., Rilling, B., Herbes, C., & Venus, T. E. (2026). Sustainability signals: The role of heuristics in consumer preferences for peat alternatives. Journal of Environmental Management, 402, 128980.