Hello Dear Growers!
This week's post will focus on timing of veraison, nitrogen and the subsequent 2026 harvest.
I have been observing the current conditions and can confidently say that we are about 7-10 days behind the last two vintages.
From the 12 varieties I monitor, Osceola Muscat is the first one to start veraison- about a week ahead of NYM or L'Acadie. The Osceola berries have JUST started to soften in some sites, while L'Acadie is still dark, green, not opaque and hard to the touch. Below are values of 3 varieties sampled on the same day for the last three years.
I can surmise that there are several factors at play here:
1. This ripening season has been wetter than the previous two vintages.
2. This ripening season has also been cooler than the previous two vintages,
3.The NITROGEN factor (VIGOUR).
Visiting the growers over the season, I have seen very dark green canopies, long internodes, excessively long shoots, 3-4 tendills on the tips of the shoots (there should only be 2).
This tells us that the vine's vigour is unchecked.
Why could this be? Last season, growers added nitrogen to their vines prior to veraison. There was no rain, therefore the ground application was left on top of the soil and was not absorbed by the vine at the time. Once the rain started, that nitrogen was taken up by the vine, stored and released in 2026. If growers applied nitrogen again in 2026, all that nitrogen is now being used to grow long, thick shoots, large leaves (causing shading), big vines, and not actually using the energy to ripen the grape clusters.
SOLUTION?
PETIOLE SAMPLES TO CONFIRM.
For a refresher on how to execute petiole collection and the nutrient ranges please see this link:
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.perennia.ca/wp-content/uploads/2024/09/Grape-Petiole-Sampling-Protocol-at-VeraisonV2.pdf
Immediate Field Practice: De-leaf more aggressively to expose the clusters to the sun and open up the canopy.
The days are getting shorter, cooler and we are still receiving quite a bit of precipitation. De-leafing is absolutely neccessary.
Do not assume you will be getting the same brix values as the two prior vintages. Unless the weather dries out quickly and stays dry for the next month, those brix values will be lower.
What to do about nitrogen?
DO NOT APPLY. You will most likely not need to apply any for at least the next year-UNLESS your site is routinely nitrogen deficient (very light green, small leaves, short canopies, no/ low cluster count. For reference:
Nitrogen deficiency
Nitrogen excess
Please remember: The leaves do not need to be dark green. Spot tread with urea if necessary, but ground applications are NOT NEEDED right now.
I will continue to sample every week until the end of harvest, so you will be seeing weekly brix and acidity updates here.
If you are seeing anything unusual on your sites, or you would like a consult, please don't hesitate to reach out.
Thank you for your time this week, and see you in the field!
Cheers!
-Katarina
Katarina Vucic P.Ag; MSc; DipWSET
Viticulture Specialist
Perennia Food and Agriculture
Email kvucic@perennia.ca
Office 902-678-7722
Cell
902-599-1390
