Post-harvest care of grapevines involves monitoring the vineyard for water and nutrient requirements, replenishing vine carbohydrate levels as well as minimising pest and disease pressure for the next season.
Temperatures in most Australian wine regions allow for vines to retain their leaves for a period of time after harvest. In cooler areas, this may only be for a few weeks, but more commonly it can extend to four months in inland regions such as Riverina.
Provided that the vine leaves remain in reasonable health and the supply of water and nutrients is adequate, continued photosynthesis and nutrient uptake during the post-harvest period can allow vines to store carbohydrate and nutrient reserves for use in the next season.
Post-harvest irrigation is important as leaves need to be well hydrated to maximise carbohydrate production from photosynthesis. The movement of water through the soil profile helps move fertilisers into the root-zone, nutrients are more accessible to the roots in moist soils and active leaf transpiration is necessary to carry the major mineral nutrients through the grapevine.
In dry soils, irrigation prior to bud-break can avoid uneven and reduced early season shoot growth.
Photosynthesis and mineral nutrition are closely linked, and adequate nutritional status is needed to maintain photosynthetic rates, while the carbohydrates produced by photosynthesis are in turn needed as a source of energy for mineral uptake.
Post-harvest irrigation is important because of its impact on restoration of carbohydrate and mineral nutrient reserves. However, where reduced water allocations or low rainfall limit irrigation options after harvest, it may not always be possible to maintain soil moisture levels for the entire period after harvest. Growers may also look to the post-harvest period as an opportunity to deliberately save some water.
The resources in this section provide further information on the roles that carbohydrates and some of the main nutrient reserves play in the seasonal growth cycle of grapevines. They discuss the conditions under which the post-harvest recovery is most likely to be needed and how irrigation and fertiliser inputs can be used most efficiently.