A drip fertigation system was developed to improve vegetable production in sloping greenhouses. The system comprised a control unit, fertilizer injection unit, feed tank, feed pump, feed valves, and nutrient reservoir, which are also used in flatland drip fertigation systems. These components were placed in the upper part of a sloping greenhouse, and dripper lines with diaphragms were installed on longitudinal ridges. However, it resulted in unbalanced irrigation along the slope because when the irrigation was complete, the nutrient solution and water remaining in the dripper lines flowed out of drippers in the lower part of the dripper lines due to gravity. This problem was solved using a newly developed system, featuring a drainpipe and drain valve installed at the lower end of the dripper lines. On completing fertigation, the drain valve, which had been closed during the irrigation, was opened. The nutrient solution and remaining water in the dripper lines then immediately flowed into the drainage reservoir via gravity and not onto the field.