Spring frost is one of the biggest challenges facing winegrowers every year. With climate change, these frost episodes are becoming increasingly frequent and intense, seriously threatening harvests.
In 2021 and 2022, many French wine-growing regions suffered severe frost damage, reminding us of the urgent need to implement effective means of protection.
In this article, we’ll explore the best techniques for protecting vines from frost, focusing on innovative, environmentally-friendly solutions.
Understanding spring frost and its impact on vines
Before discussing protection methods, it is essential to understand the phenomenon of spring frost and its effects on vines.
Gel types
There are two main types of frost that can affect vineyards:
1. Radiative frost: this is the most common type of frost in spring. It occurs on clear, calm nights, when the soil loses heat through thermal radiation.
2. Advective frost: less frequent but harder to combat, it is caused by the arrival of a mass of cold air, often accompanied by wind.
Why are vines vulnerable to frost?
Vines are particularly sensitive to frost in spring, when budburst and the first buds appear. At this stage, the young shoots contain a lot of water and are very fragile. Temperatures below 0°C can cause irreversible damage, leading to partial or total loss of the harvest.
Traditional frost protection techniques
For decades, winegrowers have used a variety of methods to combat frost. Here are some of the traditional techniques:
Candles and braziers
The use of anti-freeze candles or braziers is an ancient but still widespread method. These devices create a layer of smoke that helps retain heat close to the ground. However, this technique is labor-intensive and can have a significant environmental impact.
Antifreeze towers
Antifreeze towers, also known as wind turbines, work by stirring the air to mix layers of cold air on the ground with warmer air above. Although effective, these towers are costly to install and can generate significant noise pollution.
Water spray
This method involves spraying the vines with water, which releases latent heat as it freezes. Although very effective, it requires large quantities of water and can cause problems if badly managed.
Innovative solutions: focus on VENTIGEL™
Faced with the limitations of traditional methods, new technologies are emerging to offer more effective and environmentally-friendly protection. Among these innovations, VENTIGEL™ stands out for its unique approach.
What is VENTIGEL™?
VENTIGEL™ is a frost protection system born of collaboration between experts in aeraulic systems and winegrowers. This solution combines electric ventilation and auxiliary heating to effectively combat spring frost.
The benefits of VENTIGEL™
1. Mobility: With its width of less than 1m, VENTIGEL™ can be easily moved between vine rows.
2. Environmentally friendly: Its electric motor considerably reduces the carbon footprint compared with thermal systems.
3. Effective: The system can protect 2 to 3 hectares, with proven results even at temperatures as low as -7°C.
4. Economical: The initial investment is lower than other systems, and running costs are kept under control (less than €2/h electricity).
5. Practical: Simple to install and use, VENTIGEL™ requires little maintenance.
How does VENTIGEL™ work?
VENTIGEL™ works in two stages:
1. It ventilates the air early enough to dry out plots and prevent the formation of condensation on plants.
2. In the event of a continuous drop in temperature, it provides additional calories thanks to its integrated heating system.
Its powerful air jet (over 35 m/s) enables it to cover a large area, ensuring effective protection over several hectares.
Complementary frost protection strategies
While solutions like VENTIGEL™ offer effective protection, a holistic approach is recommended to maximize vine resistance to frost.
Grape variety selection and vineyard management
- Opt for late-budding grape varieties in at-risk areas.
- Adapt pruning and vine management to delay budburst.
- Maintain bare, compacted soil, which stores heat better during the day.
Monitoring and forecasting
- Use local weather stations to anticipate the risk of frost.
- Install temperature probes in plots for precise monitoring.
Combination of methods
Combining several techniques can offer optimum protection. For example, the use of VENTIGEL™ can be complemented by wintering sails on particularly sensitive young plants.
FAQ : Protecting vines against frost
How can you tell if your vines have frozen?
Signs of frost on vines include browning of young shoots and buds, as well as wilting. If in doubt, wait a few days to assess the extent of the damage.
At what temperature do vines freeze?
Damage can start to appear as soon as temperatures drop below 0°C, but sensitivity varies according to the vine’s stage of development and grape variety.
Why burn the vines?
The practice of burning straw bales or other materials near vines aims to create smoke that acts as a blanket, limiting heat loss from the soil. However, this method is being used less and less because of its environmental impact.
How can you protect your vines from frost on a small scale?
For small vineyards or gardens, you can use winterizing sails, mini greenhouses, or even anti-frost candles. The important thing is to act preventively and keep a close eye on the weather forecast.
Conclusion
Protecting vines against frost is a constant challenge for winegrowers, but technological advances such as VENTIGEL™ offer encouraging new prospects. By combining these innovations with appropriate cultivation practices and careful monitoring, it is possible to significantly reduce the risks associated with spring frost.
Investment in effective, environmentally-friendly solutions is crucial for the future of viticulture, in the face of the challenges posed by climate change. Systems like VENTIGEL™ show that it is possible to reconcile performance, economy and ecology in the fight against frost.
For winegrowers wishing to protect their production and ensure the long-term future of their business, the adoption of these new technologies, combined with a global approach to vineyard management, represents a winning long-term strategy.
