With harvest just about over, now is the time to consider those things that need to be done to ensure the vines go into dormancy in the best possible condition. The time between harvest and leaf fall is an important period when the vine must restore the level of carbohydrates that have been depleted by the demands of the crop. With another early vintage, there is more time for this full restoration of reserves to occur.
The most important aspect of post-harvest management is to prove adequate irrigation. Care is needed to ensure the vines are not under or over-watered. The amount of irrigation water required by vines will be immediately reduced after the removal of the crop by the percentage of leaves removed in the harvesting operation. Remember that the water requirements also decrease as leaves age and evaporative conditions decrease with cooler days and nights and shorter days. Leaching irrigations should be left until June to August.
Now is also an important time to apply nutrients, to assist in the carbohydrate restoration process. A flush of root growth occurs at this time of year and nitrogen and phosphorus are readily taken up by the vine. Approximately 30-40% of the total annual requirements of the nutrients should be applied in the post-harvest period. Nutrient uptake from foliar nutrient sprays is likely to be inefficient.
Fungicide sprays at this time are usually not worthwhile. The exceptions may be for young vines that may continue to grow new leaves for at least another month or more.
Of course, now is also a good time to clean up some of the weeds that have got away over the harvest period. Some of the troublesome perennial weeds such as couch can be effectively sprayed before they go dormant. Weeds should also be targeted before they flower, preventing the build-up of a seed bank. A reminder that best weed control occurs when weed foliage is clean and not stressed, so timing weedicides to follow irrigation or a rain event is preferable.