Market-gardening cropping systems in protected cultivation are very sensitive to soil-borne pests and diseases. Their productivity used to rely on pesticides, but alternative systems have now to be found for environmental, societal and health reasons. Many cultural techniques are known to provide some control of soilborne diseases, but are only partially efficient. The aim of the project is to design alternative systems with professionals, by improving the efficiency of the present techniques and/or imagining more innovative systems. The research project takes place in two steps. The first one consists in building a tool to assess the resistance or resilience of a given cropping system to soil-borne pests; the second one consists in using the tool with professionals in order to build alternative cropping and farming systems in cooperation. The model built for evaluation is a qualitative multicriteria tool. As scientific knowledge is not available for each technique or combination of techniques, empirical knowledge collected from growers and technical advisers is used to fill the gaps. The model is already built for root-knot nematodes and under construction for the other fungi. The second step will consist in using the tool with technical advisers and growers to redesign cropping systems and select the promising ones that should be put into trial in R&D stations. Co-building farming systems with stakeholders appears as an absolute necessity, to imagine solutions both efficient and acceptable for growers. The presentation will enable to discuss how combining expert and scientific knowledge may not only fill the knowledge gap, but also enable to build innovative solutions thanks to the diversity of experts' standpoints.