French organic vegetable farms vary from complex biodiversity-based systems with diverse crops to simpler input-based systems with fewer crops. Although this heterogeneity may reflect the conventionalization of organic farming, the environmental impacts of these contrasting production strategies remain poorly quantified. Assessing these impacts is important to inform debates on the environmental performance and future development of organic farming systems. However, diversified vegetable farms are difficult to evaluate with conventional crop-based life cycle assessment because they combine numerous crops on a small area. We therefore applied a farming-system life cycle assessment to three French organic vegetable farms: a large open-field farm, a highly diversified microfarm combining open-field and sheltered production, and a medium-sized sheltered production farm. Using functional units based on area, output mass, and value, we assessed climate change, marine eutrophication, on-farm biodiversity, land competition, and energy demand, and quantified plastic use. The functional unit used strongly influenced the ranking of the systems. Per ha, the sheltered production farm had the highest climate impact, while the open-field farm had the lowest. Per kg and per €, climate impacts varied less, with the open-field farm having the lowest. Energy demand per ha and per kg increased from the open-field farm to the microfarm to the sheltered production farm, while energy demand per € was similar for the open-field and microfarms and higher for the sheltered production farm. The open-field farm used much less plastic than the other two but had a lower biodiversity score and a higher land competition impact. None of the three systems clearly outperformed the others across all impacts. Biodiversity scores highlighted the critical role of semi-natural habitats, emphasizing the need for clear farm-boundary definitions in farming-system life cycle assessment. Estimating nitrate leaching remains challenging due to limitations of the IPCC Tier 1 model, resulting in high uncertainty in marine eutrophication estimates.