It has been a difficult end to the season for New Zealand vineyards. What looked initially like a promising harvest was interrupted by an unusually wet February and March, which left a lot of vineyards scrambling to harvest as many grapes as possible. This hasn’t been made any easier by staff shortages (thanks to the dreaded ‘spicy flu’!) and generally difficult times with restrictions. 

With a shortened harvest period, the intake hasn’t been what it could have been. However, post-harvest is a critical time to set vines up to come back stronger next season. With the right approach, you can help to boost and improve quality production in future years. 

Clean up and disease check

With heavy rain comes the risk of disease, and many vineyards have reported signs of Botrytis and Powdery mildew has also been problematic. Disease control is a season-long commitment, particularly if your vine’s nutrition is not given primary focus, which will undoubtedly lead to continued troubleshooting . A nutritionally well balanced vine certainly has less problems with disease.

Any diseased tissue should be removed and destroyed and remember to clean up debris on the ground around vines. Applications of beneficial organisms such as Superzyme create positive soils providing protection and assist in breaking the cycle of overwintering pathogens that may cause headaches next season. 

Botrytis is a perennial concern that causes a lot of damage and lost profits through bunch rot. Growers have seen significant reduction in bunch rot through applications of Biomin Calcium throughout the season [1]. Vines take up a large amount of calcium post-harvest if it’s available, so a post-harvest foliar application of Biomin Calcium can help increase resistance to Botrytis moving forward. 

Post-harvest fertilisation

The time between harvest and leaf fall is critical to ensuring vines have the necessary store of carbohydrates to get them through their winter dormancy and to ensure a strong bud break next season. Doing soil and leaf analyses should guide what nutrients to target. 

Boron deficiency can be devastating, particularly in acidic soils. Boron influences flowering and fruit set, with the often tell-tale signs of hen and chicken also known as Millerandage, as well as increasing sugar levels. Since boron is a particularly mobile nutrient, post-harvest applications can be very effective in addressing deficiencies. If boron levels are below expectation, try our Biomin Boron. 

One of the most crucial nutrients to be targeting is Nitrogen. About 30% of a vine’s nitrogen usage during the season is derived from applications the previous year. While ammonium-based Nitrogen fertilisers are a popular choice, this can lead to a significant amount of nitrogen wastage through volatilisation. However, combining the fertiliser with humic acid can greatly reduce this loss. Humic acid stabilises nitrogen retention which leads to more efficient uptake, meaning less fertiliser is needed. Try our Humax solution.

Humic acid’s ability to stabilise nitrogen appears to be linked to its probiotic effects on soil. To this end, adding Mycorrhizal fungi can produce similar effects. As with humic acid, Mycorrhizal fungi also promote root growth, and nutrient uptake which is important for vines close to dormancy. These beneficial fungi create a network of thin fibres that attach to roots and increase their effective feeding range, while also providing structure to the soil. Our Rootella line of Mycorrhizal fungi could be the perfect solution for you.

If you have questions, send me an email – [email protected]

Molly Callaghan
Director

[1] Controlling Botrytis Organically, https://rd2.co.nz/wp-content/uploads/2019/12/Controlling-Botrytis-Organically-Dr-Phillip-Elmer-Lincoln-University.pdf

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