A field study was undertaken to extrapolate the impact of foliar application of potash and its spray schedule on yield and physical and chemical parameters of sweet orange cv. Jaffa at experimental orchard, Department of Horticulture, CCS Haryana Agricultural University, Hisar. The results revealed that foliar application of KNO? at both the doses (2 and 4%) was found significantly or marginally better than K?SO? (1.5 and 3.0%) and control (water spray) in increasing the juice content. Peel content, peel thickness and rag content was found to be influenced significantly due to different treatments on K and its spray schedule. Minimum rag content (38.11%) was recorded with foliar application of KNO? at the rate of 4% and maximum with control. Ascorbic acid and acidity were found maximum with two foliar applications of KNO? at the rate of 4% in the last week of April and August. Foliar application of KNO? at the rate of 4% was found most effective in increasing yield of sweet orange over control and other K treatments. Spray of K in the last week of April, May and August was found superior in increasing yield closely followed by two sprays in the last week of April and August. The findings signify the importance of K spray in enhancing yield and quality of sweet orange under semi-arid north western conditions of India.