Sustainable compost and potting soil marketing: Private gardener preferences

Abstract

Bioenergy represents a promising approach not only to sustainable energy but also to effective management of organic waste. As an end product of bioenergy production, digestate is often treated as another waste product, although it has substantial agricultural value. Efforts to integrate digestate-based compost products into the potting soil market for home gardeners have begun, but are hampered by a lack of insight into consumer preferences. We sought to investigate customer attitudes toward digestate-based compost products by simulating a real purchasing decision through a discrete choice experiment (DCE). We collected data on 6084 trade-offs made by 507 German home gardeners in the context of making a potting soil purchase. Potting soil attributes relevant to the purchasing decision were derived from part-worth utilities generated by Hierarchical Bayes Estimation. We applied Latent Class Analysis to the decision data and were able to identify five distinct groupings of consumer preferences, each distinguished by the relative importance given to the potting soil attributes by that group. Price emerged as the predominant attribute, with both budget-conscious and premium price preferences observed. Resource origin was the second most important factor, and again triggered both favourable and unfavourable responses. A peat-free and organically labelled product was attractive to many customers, but not to others. Our findings provide insight into home gardener preferences for potting soil attributes. These insights can help current and future bioenergy producers integrate digestate-based products into the potting soil market.