2024 – a good vintage for Grasshopper Rock
With a strong El Nino event confirmed in spring 2023, the 2024 vintage felt a little more unpredictable than normal. Fortunately, cold snaps, frosts, wind, and a hail event fitted nicely around a warm dry flowering and a dry and sunny, albeit cool, ripening period. We were pleasantly surprised with a slightly larger harvest than expected with exceptionally clean fruit.
Overall, El Nino did leave its mark with a slightly cooler than average season. We recorded 896 growing degree days versus our average 943 GDD. Despite this, average bunch weights were higher than normal.
Monthly breakdown
September 2023. The last hard frost pre-budburst was a -4 deg C frost on 26 September which is nothing unusual for the time of year.
October temperatures were average with no significant events.
November growing degree days* were about 20% below average and a significant frost occurred on 26 November. With good frost fighting turned on, young shoots were undamaged. Later November was particularly windy with some strong south and southwest winds.
December growing degree days were 12% ahead of average. This meant good conditions for flowering and fruit set and the all-important heat accumulation for the October to December period was back on track after a cool November. Total GDD over this period has a significant influence on potential berry size and therefore total yields.
January 2024 temperatures were near average. There was a surprise when temperatures dropped below zero on 24 January and required sprinklers to be turned on for frost fighting.
February temperatures were average to slightly cooler than average and conditions notably drier than average. A significant hail event occurred on 2 February and was quite widespread around Central Otago. The size of the hail was sufficient to do significant damage to exposed berries. Fortunately, the timing was before veraison and the berries had therefore not accumulated sugars which would have encouraged fungal diseases. This is the first time we have experienced a February hailstorm and likely a higher risk with a strong El Nino. The outcome for us was insignificant as any damaged berries shrivelled and fell off.
March was surprisingly cold. GDD were 29% below average which set the season up for a cool finish. Frost alarms went off on six days when temperatures dropped below zero in the vines. However, a period of clear days and no rain progressed ripening faster than expected.
April harvest started a week ahead of earlier expectations. It was a frost-free harvest although temperatures dropped below zero on three nights leading into harvest. Grapes were hand-picked from 6 to 10 April over four days followed by a final pick on 18 April.
Average bunch weight was 117 g which is above average. Fruit was exceptionally clean this vintage largely due to the drier than average ripening period.
*Growing degree day (GDD) is the day’s mean temperature less 10 deg C. It is a useful measure of the heat available for growth of the vine. For example 30 days of 6 GDD = 180 GDD for the month.
30 day temperature chart
The chart below shows daily temperatures for the last 30 days leading up to the start of harvest. The blue lines mark 25 degree C and 5 degree C. March was cooler than average with slightly more nights below 5 degrees and less days over 25 degree. Ideal for slow ripening of Pinot Noir.
