Biogas digestate management: Evaluating the attitudes and perceptions of German gardeners towards digestate-based soil amendments

- Private gardeners can hardly evaluate the intrinsic value of soil amendments.
- Product price and packaging are the most important purchasing criteria.
- The product name has got a recommending effect concerning the area of application.
- Digestate as a potential raw material for soil amendments is viewed skeptically due to its biogas origin.

Managing the excessive nutrient surplus in the vicinity of many biogas plants presents an ever-increasing challenge. By opening additional markets for digestate products, plant operators can create alternative routes for their digestate streams and so lessen the economic burdens arising from digestate disposal. A relatively new and promising market is the private garden sector where small quantities of digestate-based products have already been sold with little marketing effort. This niche sector has the potential to develop into something much larger, but to do so, marketers must understand the consumer base. Guided by the consumer decision process model, we found through interviews with private gardeners from southern Germany that consumers' perceptions of value and risk in purchasing soil amendments often rely on credence attributes, making packaging and trust factors paramount in successful marketing of these products. A joint effort from key stakeholders based on these insights could lead to successful integration of digestate-based products into the mass marketplace, thereby helping both to preserve finite resources and to foster the long-term viability of biogas as a renewable energy source.