This paper uses a directional output distance function to estimate a multi-output production frontier for a sample of experimental plots grown for the Sustainable Agriculture Farming Systems project at the University of California, Davis. Cross-sectional technical efficiency indices are estimated that take into account two proxies for undesirable output: number of trips across a field as a proxy for air pollution and/or soil erosion, and pints of pesticides applied to account for potential leaching and/or health risks. Shadow price estimates based on marginal rates of transformation ranged from $8-$21 for trips, while shadow prices for pints of pesticides averaged $23-$27.