When winter rainfall is insufficient to fill up the roots with water, the plants must be irrigated before the start of vegetative growth. Irrigation continues until ripening starts. Irrigation is also necessary after ripening starts and depends on the total quantity of water available on the root depth in relation to the evapotranspiration. In shallow, light ground, irrigation will be necessary until the grapes are harvested.
Overall, for light texture soil, irrigation must be stopped to reach the water exhaustion level required during harvesting. In hot and dry climates, or when the grapes are harvested early, light irrigation may be necessary to prevent the soil from becoming too dry.