Western agricultural practices for crop protection are still heavily dependent on pesticides, even though they cause major human health and environmental hazards. In France, public incentives for pesticide reduction have failed to achieve their goal, and agroecological practices are still seldom implemented. In this study, we hypothesized that a systemic analysis of the determinants of current farming practices could serve to characterize (i) the impediments to change in farming practices; (ii) the resources supporting the change; (iii) the underpinning sociotechnical processes; (iv) the stakeholders’ involvement; and (v) levers to facilitate agroecological transition. We therefore designed the first analytical framework that supports a systemic, multi-level (field, farm, territorial, and supra-territorial), multi-actor (including private actors and policymakers), and transformation-oriented analysis of the determinants of farming practices. We applied this analytical framework to the management of root-knot nematodes in sheltered vegetable systems in south-eastern France, jointly analyzing conventional and organic systems. We conducted this comprehensive analysis based on complementary data collection methods: interviews with stakeholders, analysis of written material, participant observation, and participatory workshops. We show that strongly interconnected determinants of farming practices fostered drastic soil disinfection and locked out agroecological soil health technology (e.g., product quality and economic constraints from marketing firms and from regulations; lack of knowledge; unavailability of agroecological inputs). However, this sociotechnical lock-in was being undermined by societal pressures and increasing actions of the stakeholders in favor of the agroecology paradigm. On the other hand, the conventionalization process of the organic regime was simultaneously threatening the further development of agroecological practices. Finally, this analysis revealed levers that could be used to support innovation design and enable changes in farming practices toward agroecology (e.g., facilitate access to agroecological inputs, develop multi-stakeholder platforms). The framework, successfully applied to the Provençal vegetable sector, could be used in other production and territorial contexts.