Seasonal update 2022: GDD, veraison is almost done, vineyard protection and grape sampling

Thursday, September 8, 2022

This week, Jeff Franklin from AAFC Kentville is sharing with us weather information with quite positive values of growing degree values. Veraison started since the middle of August in the earliest hybrids and currently it’s possible to see many vineyards with grapes changing colors and ripening. With the grapes already ripening it’s important to remind to protect the fruit zone to diminish the damage by nature.

The first table shows the temperature base 5⁰ C and 10⁰ C from 2019 until 2022 accumulated from March 1 until September 6. 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 6, 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.

At this time, we can see 2022 with values higher than 2021. Compared to the 5- and 10-year average, 2022 maintains a considerable higher accumulation of degrees. The increase of degree accumulation combined with the lower amount precipitation has triggered that some grapevines, hybrids and Vitis vinifera varieties, accelerated their phenology compared previous years. Therefore, take a look at your records as harvest, as it looks quite similar to the previous seasons.

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 6, 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, 2021, 2020 and 2018 are very similar than the current season and only overpassed by the season 2006. Take a look at your records of how the previous seasons were to be prepared for harvest and have an active communication with the wineries on how they plan to proceed.


Veraison started in the middle of August with the earliest hybrids turning color, such as Baco noir and Castel, and now even the latest Vitis vinifera varieties, like Riesling, are reaching at this phenological stage. The combination of warm temperatures and less precipitation have impacted the grapevines accelerating the ripening process, which is something important to consider as harvest will approach soon. It’s highly recommended to keep an eye on how nature might impact your crop and it’s important to have the fruit zone protected to diminish damage.

Figure 3. On the left Petite Pearl and on the right L’Acadie blanc.

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

Most frequently used grape protection strategies in Nova Scotia are netting, fences, sonic devices, kites and combination of these.

One of the most common ways to protect the bunches is the netting. The nets are placed in a way that the fruit zone is covered from the top of the bunches until below the first wire. In some cases, nets can be placed in a way that they cover 2 rows completely at a time. Regardless of the coverage method selected, it’s important to ensure proper coverage of the fruit zone. It’s necessary to fasten the edges of the nets with staples/clips/pegs, to prevent birds or racoons from entering inside. 

Figure 5. Vineyard during the process of netting the fruit zone.

Electric fencing is used as a strategy to prevent raccoons from visiting the grapevines. For the most efficient results, protecting the entire perimeter of the property is necessary. Moreover, to ensure the correct voltage along the whole fence, the area where the wires are located must be connected properly. Making some measurements prior to setting up the fence is recommended. Keeping the area clean from weeds will prevent short circuiting and allow the proper functioning of the electric fence. Also, it is important to connect properly the fences to have a good protection throughout the perimeter.

Figure 6. Electric fence protecting the perimeter of the vineyard and the connection between two fences.

Sound repellents that are used to help with the protection of the vineyard include sonic devices and cannons. Please, take a look at the previous publication to read more about Nova Scotia Sonic Device Policy - Wildlife Deterrent.

Figure 7. Kite combined on the left with netting and on the right with a sonic device.

Last, but not least, at this time 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. Finally, Alab from Acadia University provides analytical services for grape ripening, please take a look at the lab webpage for more information