General varieties of oranges stop growing at MINUS 5 ~ 6℃, and frostbite occurs at 0℃. Some varieties of oranges, such as kumquat, stop growing at 0℃ and get frostbite at -2℃. Of course, a short period of 0℃ or -2℃ will not cause excessive frostbite, but will naturally freeze to death. How do orange trees survive in Qingdao? There is only one way in winter, put it in a greenhouse, or plant it in a pot and put it at home. Because it was originally produced in the south, it has always been sensitive to the demand for temperature. Although I like warm and humid climate, my cold tolerance is slightly stronger than that of pomelo, lime and sweet orange. But when the temperature is lower than -5, freezing injury may occur.
Orange tree is a subtropical tree species, which is not cold-resistant, and it is vulnerable to freezing injury in winter north of the Yangtze River. Be sure to put it indoors in winter in the north, it is easy to freeze outdoors, and the room temperature is preferably above -2℃. However, it is still possible to spend the winter outdoors in the first line of southern Shaanxi. Degree. Even if the temperature difference is 0.5℃, sometimes there will be completely different results. The growth and development of citrus need a temperature of 65438 02.5 ~ 37℃. The day and night temperatures of flower bud differentiation in autumn are about 20℃ and 65438 00℃, respectively, and the soil temperature of root growth is roughly the same as that of aboveground growth. In winter, it is necessary to provide proper light for orange trees so that plants can carry out normal photosynthesis, and it is best to keep them in a sunny environment.