To provide a method for cultivating crops solving the following problems in a conventional frostproof fan: depression-angle adjustment relies on manpower, or wind is blown in such a condition as to set the depression angle when a construction pole is extended (to be at a high position), so that the frostproof fan device is further improved to result in reinforcement in harvest of high-quality fruits where securement of bearing in fruits, reduction in scar skin, promotion of enlargement of fruits and securement of fruit shapes are performed so as to meet demand in the market.

The method for cultivating crops through using a frostproof fan set on an elevating construction pole in a farm field so as to freely adjust the depression angle comprises the following process: extending the construction pole so as to maintain the frostproof fan at a depression angle condition so that warm air blows down for frostproofing the crops; shortening the construction pole so as to maintain the frostproof fan in almost horizontal condition so that the air is brown in almost horizontal direction for prevention from cracking of fruits; and covering the crops with another greenhouse for prevention from cracking of fruits.