What are the environmental conditions requirements for grapes?

The climate, soil and moisture in the external environment have a great influence on the growth and development of grapes. Grapes have certain requirements for environmental conditions.

(1) Temperature Grapevine is a temperature-loving fruit tree. When the daily average temperature reaches above 10℃, the buds begin to germinate. The optimum temperature for shoot growth and flower bud differentiation is between 25°C and 30°C. When the temperature reaches above 40°C, the leaves will be damaged and the fruit will suffer from sunburn. The optimum temperature for berry ripening is 28°C to 32°C, and temperatures below 14°C and above 38°C are detrimental to fruit growth. A certain amount of heat is required from germination to full maturity of the fruit, that is, an active accumulated temperature of ≥10°C (Table 1). Insufficient effective accumulated temperature results in berries with low sugar content, high acid content, poor coloration, and reduced quality.

The cooling requirements of grapes through dormancy in winter are shown in Table 2.

(2) Water Grapes have well-developed root systems, strong water absorption capabilities, and strong drought resistance, but young trees have poor resistance. Generally, grapes require more water during the budding period, the vigorous growth period of new shoots, and the berry growth period. Rainy or humid weather during the flowering period affects normal flowering and pollination. Heavy rainfall during the ripening period of berries affects coloration, causes fruit cracking, aggravates diseases and reduces quality. There is too much rain in the late growth period of grapes, which results in late growth of new shoots and poor branch maturity, which is not conducive to overwintering.

(3) Light Grapes are light-loving plants and are very sensitive to light. With sufficient light, the plants grow vigorously and fully, the flower buds are well differentiated, the berries color quickly, the quality is good, and the yield is high. If the light conditions are insufficient, the branches will be thin and weak, with long internodes, insufficient tissue, poor flower bud differentiation, low yield, and poor quality. However, if the light is too strong, the fruits are prone to sunburn.

(4) Soil Grapes are very adaptable to soil and can be grown in any soil except extremely clayey soil and strongly saline-alkali soil. However, sandy loam soil with deep, fertile soil, loose soil, and good ventilation is best. Grapes grow well when the soil pH is 6 to 7.5. When it exceeds 8.3 to 8.7, yellow leaf disease or leaf edge dryness is prone to occur. When the soil salt content reaches 0.23%, grapes begin to die, especially young grapes that are less tolerant to salt-alkali.