Seasonal update 2022: GDD, ripening, harvest and storm preparation

Thursday, September 22, 2022

Jeff Franklin from AAFC Kentville is sharing with us the weather information with positive values of growing degree, but not as high as the previous weeks. Hybrids have already started harvest; these grapes reached the values required by the wineries and decided to start picking for specific wines. Just remember, it’s always important to reach out the wineries to know which are the grape ripening requirements and when would be the best time to harvest the grapes.

The first table shows the temperature base 5 C and 10 C from 2019 until 2022 accumulated from March 1 until September 21. At the end of each section, it’s possible to see the average of the last 5 and 10 years respectively.






5 year average

10 year average

Plant development (Base 5ºC)







Insect development (Base 10º)







Figure 1. Degree day accumulations as of September 21, 2022.  All data are taken from the Kentville weather station, based on a start date of March 1, and calculated using the single sine method.

The last week the degree days increased, but not at the pace as the previous weeks. Compared to the 5- and 10-year average, 2022 maintains a considerable higher accumulation of degrees. The increase of growing degree days has sped up the fruit ripening, therefore, keep an eye on the vineyard, your records and when grape samples are collected inform to the winery..

In the following column graph, you can see the values from 2005 until 2022 and at the end the average of the last 5 and 10 years respectively.

Figure 2. Degree day accumulations as of September 21, 2022 base 10⁰ C. All data are taken from the Kentville weather station, based on a start date of March 1, and calculated using the single sine method.

Already mentioned in the previous table, 2022 the accumulation is higher than previous seasons and it is higher than the 5- and 10-year average. Compared to previous seasons of 2021, 2020 and 2018, it’s very similar to the current season and only overpassed by the season 2012. Depending on varieties and locations, ripening will move differently, for that reason it’s important to keep notes and compare with your previous records.

 Ripening is moving through all the varieties in the province and with the shift of temperatures, it can diminish the speed of sugar loading and drop of acidity. Depending on the winery goals, it might be necessary to harvest earlier or later in the season. To know when the most convenient harvest date is, it’s important to reach the winery and establish an active communication plan to coordinate the harvest. The winery might request information to be able to take the best decision depending on the wine expected to be produced.

Figure 3. On the left Lucie Kuhlmann and on the right Seyval.

Figure 4. On the left Chardonnay and on the right Pinot noir.

Meanwhile ripening is moving along, some growers have already started harvest with the earliest grapevines depending on the winemaking purposes. Mentioned a couple of times in this post, active communication with wineries is fundamental to have the grapes harvested depending on the wine goals. It’s important to track grape ripening to help taking harvest decisions and inform to the winery on how the maturity is moving along in your vineyard. Remember, the results will be as good as the sampling performance. The sampled grapes need to be representative of the plot that they are coming from. It’s a good idea to collect a minimum of 100 berries from a specific variety and repeat in the same area(s) to be able to track the ripening process. Alab from Acadia University provides analytical services for grape ripening, please take a look at the lab webpage for more information  


To finish, a storm is coming the next couple of days and it’s necessary to keep in mind a couple of things. 

  • First, if it is possible, it is convenient to take out from the vineyard wailers, canons and fences to avoid damage due the wind.
  • Second, all the vineyards with higher yields and big canopy might be more susceptible to trellis damage due the high winds. Therefore, keep in mind that potential damage can appear in specific vineyard sections and these places will have the priority. 
  • Third, in case to have berry split, it’s probable to have botrytis infections in the vineyard. It’s important to scout areas with more susceptible grapevines for berry split, are with already botrytis symptoms and varieties to be expected to be hanged until later in the season. Dr. Wendy McFadden-Smith from OMAFRA wrote an article about Pre-Harvest pest problems in the vineyard, 2022, there you will find more information about products and strategies to manage botrytis and sour rot. 
  • Last, keep notes of which areas in the vineyard have damage and lost of crop, if it’s applicable, to contact crop insurance.