This paper presents the results of the investigation on the effectiveness of UAV-based remote sensing data in determining lettuce nitrogen and water stresses. Multispectral images of the experimental lettuce plot at Cal Poly Pomona’s Spadra farm were collected from a UAV. Different rows of the lettuce plot were subject to different level of water and nitrogen applications. The UAV data were used in the determination of various vegetation indices. Proximal sensors used for ground-truthing included: handheld spectroradiometer, chlorophyll meter, and water potential meter. Relationship between the aerial and proximal sensor data are shown and discussed. Also shown is the relationship between the sensor data and plant height and leaf numbers.