Rain shelter houses are roofed with plastic film and other waterproof materials to shelter crops from rain. The houses are effective in reducing crop damage caused by diseases and insect pests, in promoting crop growth, and in achieving stable production of high quality vegetables. Thus, the use of rain shelter houses is highly effective measures in vegetable production. Particularly in heavy rain areas, its effectiveness is quite high. However, the cultivation under rain shelter houses involves several problems. It induces higher cost of production as compared with the open-field cultivation, and the houses are liable to be damaged by strong wind. Furthermore, highly advanced techniques in watering and fertilizer application are required for the success of the cultivation under rain shelter houses.