At the beginning of this week some parts in the province were hit by the first frost of the season and in some cases the temperatures decreased below zero. It’s important to keep in mind that those areas affected with low temperatures will have change in the canopy, turning color to yellow, red, getting brown in some cases and starting to fall. Also, Jeff Franklin from AAFC Kentville is sharing with us the weather information of growing degree days, which is slowing down as October is starting. Hybrids are still being harvested and getting close to the end, while vinifera varieties are in harvest mode. 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 5⁰ C and 10⁰ C from 2019 until 2022 accumulated from March 1 until October 4. At the
end of each section, it’s possible to see the average of the last 5 and 10
years respectively.
|
Category |
2019 |
2020 |
2021 |
2022 |
5 year average |
10 year average |
|
Plant development
(Base 5ºC) |
1805.8 |
1984.2 |
2056.6 |
2029.3 |
1962.3 |
1974.5 |
|
Insect development
(Base 10º) |
1038.6 |
1229.6 |
1236.5 |
1222.9 |
1180.4 |
1187.7 |
Figure 1. Degree day accumulations as of October 4, 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.
Like last week the accumulation of degree days has slowed
down as the season is moving on and the first frosts at the beginning of this
week. Compared to the 5- and 10-year average, 2022 maintains a considerable higher
accumulation of degrees. It’s possible to see a slightly difference with 2021
and the biggest difference is compared to 2019. Keep track in your vineyard on
how the look the current conditions, grape quality conditions and the harvest
dates for future management decisions.
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 October 4, 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.
Mentioned in the previous table and lasts weeks, in 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 the varieties and locations, ripening will move differently, for that reason
it’s important to keep notes and compare with your previous records.
The first fall frosts happened between Monday and Tuesday
this week, reaching different minimum temperatures and durations depending on
the location, the topography of the vineyard in each area. With this shift on
the temperature, the grapevines, depending on their tolerance to these low
temperatures, will show color change in their canopy. In the case of the vines
have been already harvested and have been affected by the frost, they will
start to slowly shut down and lose their leaves throughout the rest of season.
On the other hand, the plants with crop and that have been affected by the
frost will start to slow down the sugar accumulation on the grapes and will
start to lose their leaves as well. It’s important to keep calm, inform to the
winery your current condition and evaluate on how to proceed with them at
harvest. Always an open communication and description of your current
conditions with the winery will help to take the best decisions.
Figure 3. On the left Frontenac and on the right Chardonnay.
Figure 4. Frontenac
canopy with frost damage.
Figure 5. Chardonnay
canopy with frost damage.
Harvest is moving on in many varieties, with hybrids in process since a couple of weeks ago and vinifera ones being harvested in different varieties. Already mentioned 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 https://alab.acadiau.ca/wine.html