In spring, Quebec winemakers who have covered their vines with geotextiles to protect them from the winter cold must remove them. But when is the best time to do so? Between personal experiences and scientific data, there are often no definitive right or wrong answers.
Andréanne Hébert-Haché and her team at the Mirabel Agri-Food Research Center (CRAM) have studied this question. They analyzed vineyard yields based on the timing of geotextile installation and removal over five sites, using three grape varieties and three types of geotextiles, over the course of three winters.
The conclusions of this study, conducted from 2018 to 2021, showed that the timing of geotextile installation and removal has varied impacts depending on the sites, grape varieties, and years. However, a trend emerged regarding the optimal timing for removal.
“Our research has shown a slight reduction in survival rates and yields when the geotextiles are removed late,” explains the researcher specializing in northern viticulture.
Why? It is known that the maximum heat observed in spring creates a greenhouse effect under the geotextiles.
“What we don’t yet fully understand is how this causes damage to the buds and affects yields,” notes Andréanne Hébert-Haché. “We know that vines need warmth to bud [editor’s note: the awakening of the vine], but too much heat just before budding doesn’t seem to be a good thing. On the other hand, if the geotextiles are removed too early, the vines could be damaged by a late-season cold snap.”
“This is a challenge unique to Quebec,” the researcher points out. “In some regions, there may still be a lot of snow in the vineyards at the beginning of April, making the fields inaccessible and storing wet geotextiles undesirable. Each winemaker must make decisions based on the specific conditions of their vineyard.”
Between the still not well-understood physiological realities of the vine and practical considerations, the data from CRAM’s research can complement the hands-on experiences of seasoned winemakers.
The Knowledge of Experience
Yvan Quirion, from Domaine St-Jacques, is one of them. He is credited with introducing higher-quality, less dense geotextiles that are now widely used by most Quebec vineyards to protect Vitis vinifera varieties (Chardonnay, Pinot Noir) and French hybrids (Vidal) from the cold.
Since 2006, he has experimented with various methods of installing and removing geotextiles, developed equipment for the process, and tested different materials and timing for their removal. Through continuous exchanges with fellow winemakers like Charles-Henri de Coussergues of Vignoble de l’Orpailleur, Michael Marler of Vignoble Les Pervenches, and many others who sought his advice, as well as with researchers, he has advanced the collective knowledge on this critical issue at the heart of Quebec viticulture.
“In my view, the best time to remove the geotextiles is sooner rather than later, but I say this with many caveats and a lot of humility,” he says. “I initiated a technique that works, but we’ve refined it through our own trial and error, as well as that of others. There’s no one-size-fits-all solution.”
The winemaker recalls a new colleague who kept his vines under geotextiles for a longer period, hoping to artificially provide additional growing degree days. However, he lost part of his harvest because the vines budded too quickly and were later damaged by a late frost.
“There’s also a matter of intuition, based on experience, but also on the conditions of each vineyard,” the winemaker believes. “What is your terroir, your growing season, your climate? How was your vine prepared for winter—its pruning, its lignification? Did you have frost in the fall? Every year brings its own challenges, so I tell new winemakers to take notes and ask questions. Nothing saddens me more than seeing a winemaker lose part of their harvest because they didn’t ask questions or seek advice!”
The invitation is open. If you have questions about the best time to remove your geotextiles, give Yvan a call! And to wine enthusiasts, the next time you enjoy a Quebec wine in the spring, think of all the experiments, trials, and errors that made it possible for you to savor it.
