The beginning of veraison

Thursday, August 20, 2020

The 2020 growing season has been progressing with warm temperatures, which has impacted the plant development and accelerated their phenological stages. Even though the beginning of the season was cold, and the bud burst was delayed a couple of days, the increase in temperature has helped catch the grapes up to the key stages, such as veraison. Since the week of August 10, some of the early varieties have slowly started to change berry colour, for example, Lucie Kuhlmann and Marquette, depending on the location of the vineyard. The Growing Degree Days (GDD) based on 10 ÂșC measured till August 18 at the Kentville Research station were registered as 902.1, which are above average of the last 5 and 10 years with 824.4 and 839.7 respectively. Compared to 2019, on the same date, the GDD were 758.3, which makes a difference of 143.8 GGD between 2019 and 2020.

Graph 1. Growing Degrees Days (GDD) till August 18, with the average of the last 5 and 10 years

As previously mentioned, early varieties, such as Lucie Kuhlmann and Marquette, have slowly started veraison during the week of August 10. Currently, these varieties are more advanced in terms of phenological stage, with approximately 50% of veraison, depending on the location of the vineyard.

Figure 1. On the left Lucie Kuhlmann in the valley on August 10 and on the right Lucie Kuhlmann in the valley on August 19.

Some of the white varieties are also starting to change berry colour, such as Frontenac blanc and L’Acadie blanc during the week of August 17. In the case of Vitis vinifera varieties, it is important to consider a slight delay compared to the hybrids, which can vary from a couple of days to 2 weeks (it’s always important to consider the conditions of the location and varieties).