At what temperature should grapes be covered? What is the minimum temperature that grapes can withstand?

Growing grapes in the Russian climate is impossible without winter protection. Even winter-hardy vine varieties will die in severe frosts without protection. Young plants are particularly vulnerable to cold temperatures. Failure to cover grape vines at the correct time often leads to frost or damping-off. Therefore, it's important to know when and at what temperature to cover grapes for the winter.

The need for preparatory measures

Preparing grape plants for the upcoming cold weather varies significantly depending on the characteristics and varietal characteristics. Among them, there are varieties that are very sensitive to cold temperatures and those with good winter hardiness. The climate conditions of the growing region are also crucial. Only after analyzing all the collected information can a plan for preparing the plant for winter frosts be developed.

Based on their ability to withstand adverse weather conditions during the winter months, all varieties of this crop are divided into the following subgroups:

• unstable to cold, when they cannot withstand temperatures down to -10 degrees;
• less resistant ones successfully overwinter in frosts down to -17 degrees with their buds fully preserved;
• moderately resistant ones are able to successfully survive the winter with temperatures dropping to -21 degrees, retaining up to 60% of their buds;
• highly resistant species overwinter at temperatures down to -27 degrees, preserving up to 80% of their buds;
• Highly resistant ones are able to successfully withstand winter temperatures down to -28 degrees while fully preserving their buds.

Every grape variety needs to prepare for the coming cold weather, but the list of necessary measures varies from case to case. When planning autumn work, consider that the roots of this crop are more sensitive to frost than the vines themselves. Mature plants, unlike young ones, tolerate lower temperatures better.

For areas with cold winters covering grape plants This is essential. Temperatures there often drop below -30 degrees Celsius in the winter months. Therefore, reliable shelter is essential for the plant. Vineyards growing on sandy soil require especially careful insulation due to the high risk of frost damage.

Frost resistance and winter hardiness

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The concepts of winter hardiness and frost resistance differ. The former refers to a plant's resistance to adverse winter weather conditions. The latter refers to how well a vine tolerates subzero temperatures.

To improve winter hardiness, some of the side shoots are removed in August and the vines are left to fully ripen. For the winter, grapes must be insulated.Shoots no longer than 2 meters maintain their viability best. Therefore, grapevines are not overwatered or fertilized to avoid prolonging and intensive growth. The last time the vines are heavily watered is in August.

Improving the winter hardiness of annual and biennial plants is essential. Such plants must be covered for the winter. The area around the trunk must be covered with soil, and in winter, snowfall is added. To eliminate dew-prone roots, dig pits. This strengthens the deep-lying roots.

Non-fruiting plants are not watered or fertilized in August. The remaining plants are harvested before the first frost.

Dangerous frosts for grapes

Once dormant, grapevines can easily withstand relatively low temperatures without protection. However, this isn't always sufficient for successful overwintering. Therefore, most table grape varieties are left uncovered before winter.

Perennial trunks and branches withstand frosts most successfully. One-year-old vines are less frost-resistant. The buds of table grape varieties can withstand temperatures from -15 to -24 degrees Celsius. The central buds of the bud are most sensitive to frost, while the replacement buds show greater resistance. Dormant buds of perennial vines exhibit the most significant frost resistance.

European grapevines' buds freeze when temperatures drop to -20°C (-4°F), and their vines die at -22°C (-22°F). Older vines can experience temperatures as low as -26°C (-26°F). Vitis amurensis varieties exhibit the greatest frost resistance, remaining viable even when temperatures drop to -40°C (-40°F). American grapevines' frost resistance reaches -41°C (-41°F).

At what temperature do grapes need to be covered?

When determining the timing of covering grape plants for the winter, the territorial location of the region and the characteristics of the weather and climate are taken into account.

In regions with mild winters and warm climates, such as southern Russia, Ukraine, and Crimea, only varieties with poor frost and wind resistance are covered. Preparatory work is carried out in November or early December. In temperate regions, Belarus, and the Volga region, insulation work begins in early November.

Vines are covered even earlier in the Bryansk and Leningrad regions and in the Moscow region. Here, all preparatory work begins immediately after the leaves fall in the second half of October. In northern Russia, Siberia, the Urals, and Transbaikal, vines are insulated before frost and snowfall. Preparatory work begins in mid-October.

When asked at what temperature to cover grapes for the winter in temperate climates, experts recommend waiting until the average daily temperature drops to -5 to -8 degrees Celsius. These temperatures are optimal for beginning preparations. At this temperature, nighttime frosts down to -10 degrees Celsius can occur, and daytime temperatures warm up to 0 degrees Celsius.

At this time, the grapevine sheds its leaves, nutrients and water are absorbed into the ground and reach the deep roots, the plant's buds become dormant, and the shoots dry out. This happens before the expected time. cover the vine No need. The danger here is that any warming can trigger the plant's awakening. The bush will rot, the sap will start to flow, and the plant will die partially or completely.

Don't delay preparing for winter too long. This will cause the plant's shoots to dry out and break easily.

How to determine when to cover a plant

When determining the time to begin preparatory work, experienced gardeners advise closely monitoring weather changes to avoid missing the right moment. The first stage is typically carried out in late September, but if the region has a warm climate, this period is pushed back to early October. The process of hardening and ripening the vines is prolonged as much as possible. During this period, glucose is synthesized from starch. Sugar helps the plant survive the winter.

Without hardening, there's a high chance the grapes won't survive the winter, even with cover. The first stage of preparation takes place at temperatures between 0 and 10 degrees Celsius. The next stage occurs when temperatures drop to -6 degrees Celsius. If one of the hardening stages is impossible due to bad weather, it is carried out under cover. Each period lasts 7 days or more.

In conclusion

By following the basic rules, determine the time covering grapes for the winter It's not difficult. Preparatory work begins with the first frost. Don't delay to keep the buds and shoots alive. Timely interventions will guarantee a successful wintering and a bountiful harvest.