The growth, development, flowering and fruiting of citrus are closely related to environmental conditions such as temperature, sunshine, moisture (humidity), soil, wind, altitude, topography and slope direction, among which the temperature has the greatest influence. Even if the temperature is different, sometimes there will be completely different results. The optimum temperature for citrus growth is ~ 37℃. When flower buds differentiate in autumn, the temperature of day and night is required to be about 20℃ and 10℃ respectively. Too low a temperature will freeze oranges. In addition, oranges are shade-tolerant trees, but good sunshine is needed for high quality and high yield. Generally, areas with annual sunshine hours 1200 ~ 2200 hours can grow normally.

If Nanjing meets the above citrus growth requirements, it can be planted.