Society faces an urgent need to move agriculture toward more environmentally sustainable practices to reduce greenhouse gas emissions, biodiversity loss, and water pollution. Mandatory policy tools, such as regulations, are unpopular with farmers, notoriously difficult to enforce, and politically challenging in the United States. Instead, social norms—descriptive, dynamic, and injunctive—may be critical levers for scaling up conservation practices. In this study, we analyze the predictive power of social norms on three practices, two of which benefit conservation (no-till and cover crops) and one that is likely harmful to conservation (fall nitrogen fertilizer application). Farmers (N = 585) in four U.S. states (Illinois, Indiana, Maryland, and Pennsylvania) completed a survey indicating perceived social norms and adoption of each practice. Logit models of practice adoption demonstrate that different types of social norms predict each of the three practices. We find that social norms are correlated with practices that are both helpful and harmful to conservation outcomes. Descriptive norms are associated with no-till adoption, while dynamic norms are associated with the use of cover crops. Both descriptive and injunctive norms are associated with fall nitrogen fertilizer application. In line with previous work, we also find that self-efficacy, response efficacy, farm size, and farm income are statistically significant predictors of the adoption of each practice. Future research would benefit from examining the role of different types of social norms in more contextually specific areas of farm management and at different junctures in the prevalence of management practices within a farming community, whether emerging, well-established, or declining in use.