Spring frosts, a danger for vines and future production.

Spring frosts, an increasingly frequent risk also due to climate change, can seriously compromise the shoots and future production

In recent years we are witnessing climate changes that we can no longer ignore.

Winters are becoming increasingly warmer, shorter and springs are increasingly earlier and, for us winemakers, an increasingly frequent risk is that of spring frosts.

What happens in detail?

The vine plant, like many other plants, uses the winter cold to move the sap into the roots, accumulate it and then spread it back into the plant as temperatures rise in spring.

During this period, dry pruning is performed: the shoots are woody and the buds are dormant. It is therefore the ideal time to avoid damaging the plant.

When temperatures rise, the sap starts circulating in the lymphatic vessels again and reaches the buds.

These begin to swell and generate the new shoot, with new leaves and small bunches. The development period of the bud and the shoot is very delicate and a sudden drop in temperatures is detrimental to the survival of the shoot itself.

Spring or late frosts.

The phenomenon of spring or late frost is greatly feared by winemakers, because it occurs just when the buds have already opened and the shoot is forming.

Conditions favorable to frost occur during the night following a clear day, without clouds and wind, in which the sun warms the ground. During the night, the ground releases the accumulated heat, which rises upward and creates an inversion between warm and cold air in the atmosphere, causing temperatures near the ground to drop sharply.

The consequences can be of varying severity, from the “burning” of some shoots, with a consequent reduction in grape and wine production, to the death of the plant itself.

Spring frosts, and guyot training.

A very serious problem to face for those of us who grow Guyot vines, can be the loss of one or more shoots in the strategic position of the future renewal. In this case, the following year we do not have shoots available to bend and we must set up the structure of the plant again from a lower point, affecting the production for that year too.

Early varieties are the most at risk as sprouting occurs prematurely.

Spring frosts, significant damage to the Ciliegiolo.

Among the varieties we grow, the Cherry tree it is the earliest in its phenological stages. Last year we already had problems with a frost that occurred around the end of March when our Ciliegiolo, with shoots of just 5-6 cm, suffered a 30-35% loss in shoots.

Unfortunately, there are not many actions to take to prevent this major weather problem, other than lighting fires in the vineyard, as we see these days in various areas of Italy and France, or spraying water to create a sort of frozen protective veil that paradoxically protects the plants below. This veil ensures that the temperature of the buds or shoots below remains constant.

In our small reality we have tried to postpone the pruning of the Ciliegiolo in order to delay its budding.

In fact, a plant pruned late, when the buds are already starting to “awaken”, is inhibited from budding, having to first repair the pruning wound.

In this way we gained about ten days that could be very useful for preserving the gems.

Despite this, however, the frost of the last few days has damaged some of the new shoots, those that had already awakened.

Later varieties, such as Cabernet, do not appear to have suffered any particular damage.

Unfortunately, native varieties are more “fragile” in the face of climate changes, such as frost or drought, so international varieties are often favored in new plantations. However, it is very important to preserve them in order not to lose the territorial heritage.

by Silvia Cirri and Linda Franceschi