A Gradual Onset of Frost Benefits Grapevines, but Extreme Temperatures Could Threaten Sensitive Vineyards
South Moravia, 15 January – The beginning of this week brought a sharp cold snap, with temperatures in Moravia dropping below −12 °C in places. According to winemakers, however, the situation posed no immediate threat to the vines. On the contrary, a gradual onset of frosty weather is actually beneficial for vineyards.
The risk of damage to grapevines arises mainly during prolonged periods of very low temperatures, typically below −20 °C. Such frosts can be particularly harmful to more sensitive varieties and to young vineyards, whose root systems and resistance to extreme conditions are not yet fully developed.
"From the point of view of vineyard health, it is a good thing when the cold arrives gradually. It gives the vines time to adapt and harden off for the winter. Sudden, deep frosts without any prior cooling would be far more problematic for them," confirms Petr Ptáček, Viticulture Manager of the BOHEMIA SEKT Group.
Frost itself is natural for grapevines in winter and, in most cases, beneficial. It helps reduce the occurrence of certain diseases and pests and allows the vines to go through a natural "cleansing" process. According to winemakers, the ideal combination would be frosty weather accompanied by snow cover, which acts as natural insulation while also protecting the soil and the root system.
PIWI varieties – resilient crossings bred primarily for their resistance to disease – are a chapter of their own. For these varieties, there is still a lack of long-term data on how they behave in more severe frosts. "We are still learning and gathering experience in this area. You could say that together we are building new know-how that will be important for the future direction of viticulture," adds Petr Ptáček.
The weather so far gives no cause for concern. Nevertheless, winemakers will continue to monitor its development closely, particularly with regard to the length and intensity of the frost period.