Objectives: To characterize working hours of adult farm owner-operators and their spouses by season, and to examine associations between working hours and farm safety practices affecting children. Methods: We conducted a secondary analysis of cross-sectional survey data collected as part of an existing study of injury and its determinants. Results: Owner-operators reported a median of 60 to 70 hours of farm work per week during warm weather months, with declines in hours over the winter. Spouses reported similar seasonal patterns, although their median reported hours were much lower. Longer farm working hours by owner-operators were marginally associated with increased exposure of teenagers to farm work hazards. Exposures of young children to worksite hazards rose in association with longer farm working hours by spouses. Conclusion: Exposures of children to farm worksite hazards and demands may be consequences of adult long working hours.