Governments and environmental groups seeking to solve agri‐environmental issues, many of which are localized, must understand how farmers choose production practices. In recent decades, agri‐environmental discourse in the United States has identified two seemingly distinct styles of agriculture—“conventional” and “alternative.” However, this dichotomy is not reliably observed nor predictive of a farm's local environmental impacts. Using a unique framework combining practice theory and cosmovision, we analyzed interviews with 23 farmers along Oregon's Willamette River to explore how production decisions arise from social, economic, and structural factors and farmer environmental values. Results echo conclusions from previous studies to show that self‐identified “conventional” and “alternative” farmers have distinct characteristics, challenges, and rely on different institutions for support. However, we find nuanced within‐group variability and between‐group similarities in their cosmovisions, which often involve conflicting ethics and worldviews and combine with practical constraints to navigate farming decisions. This understanding informs approaches to working with farmers to improve environmental outcomes along the Willamette River in Oregon, while a similar nuanced approach to influencing local farm decisions can be adopted elsewhere.