The "sustainable orchards" group enables us to wonder about the production and the exchange of knowledge in agronomy. It gathers several kinds of operators in collective situation to share experiences and to think together. It also helps us to define a suitable environment, to identify the contribution of the several operators and to wonder about the achieved learnings. The group gathers fruit producers, experimenters, advisors and agricultural scientists. They think over together to propose new configurations of orchard. They try to make it more autonomous and better-balanced to promote a more efficient natural regulation. Six social conditions in the interaction and in the co-design are identified. The role of the facilitator and the contributions of each kind of operator are specified. If the objective of the group is shared by its members, some controversies remain. They contribute to the construction of a common culture by offering opportunities of interaction. The process of knowledge building isprogressive, interactive, iterative, recursive and specific to each person. The "sustainable orchards" group is a way to propose and to test different modes of production in the fruit sector which is among the most intensively sprayed productions.