What a pleasure, when the sunny days return, to enjoy a glass of a good bottle of wine on the terrace or by the pool. But on the vineyard side, summer is not synonymous with vacation, and winegrowers are preparing for the most important stage in the world of viticulture: the harvest period. Let's take a look at what our winegrowers are doing in their vineyards in summer while we bask in the sun.
The vine cycle before, during and after summer
To better understand how summer is a crucial season in viticulture , let's take a look at the vegetative cycle of the vine during this period.
The vines before summer
In spring, the vine is reborn from its ashes, and flowering and fruit set take place from the month of May. The first flowers bloom, and then comes the period when these fertilized flowers transform into fruit. Summer in the vineyards begins with the blossoming and ripening of these pretty berries . The grapes will then gradually grow, until they become beautiful, large green fruits.
Of course, for this process to take place correctly, the weather conditions must be favorable, and winegrowers remain vigilant during the summer period, to protect the vines from possible vagaries of the weather. As a general rule, the development of grape clusters requires a mild and sunny climate, with little precipitation.
Vines during the summer
After the fruit setting stage, comes veraison , which takes place between July and August. During this 6 to 8 week stage, the development of the clusters continues, and the grape berries change. White grape varieties go from a pretty opaque green to a light, translucent green, while black grape varieties first take on a pink color, before turning red, and sometimes bluish black.
The grape growing cycle ends here, and the ripening of the bunches can begin.
Vines at the end of summer
During the ripening period, the grapes become full of sugar and develop their aromas, while the acidity becomes less strong. Visually, it is more on the side of the branches that the change operates. The green branches take on a dark brown hue, and the branches supporting the vines become more robust, to support the weight of the clusters. This process is called augusting , and takes place, as its name suggests, throughout the month of August. It ends with the arrival of autumn, and more particularly with the fall of the leaves.
Generally speaking, the winegrower considers that ripening reaches its end 120 days after flowering, and 45 days after veraison. This is a rather effective way to define the harvest date .
Working in the vineyard in summer
Before the arrival of summer, the winegrower worked diligently on the soil to optimize fertilization. After weeding, grassing and adding green manure, work is now focused on the rows of vines.
Summer work: pruning the vines
Before summer, the winegrower was responsible for leaf removal and pruning, to help the vines grow. This work continues throughout the summer period and until veraison, through different operations. Thus, after having carried out winter pruning, on vines without fruit or leaves, the winegrower moves on to summer pruning, or green pruning .
The objective is to allow the vine to concentrate all its energy on the most fertile clusters and branches, limiting the development of less efficient stems and branches. There are then two types of pruning in summer :
- The size of the fruiting stems , which bear grapes. The goal here is to prune the ends of the branches, so that they do not take over the fruit;
- The size of fruitless stems, or non-fruiting stems . The stem is then cut to a length of 50 centimeters.
After pruning, the winegrower carries out leaf stripping, to ensure better exposure of the bunches to the sun, for better aeration of the bunches of grapes, and to limit the development of diseases.
Summer work: green harvests
In the middle of July, winegrowers can make the decision to carry out a green harvest . This optional step can be interesting when there are too many bunches of grapes. The goal is then to pick up some of them, in order to allow the vine to concentrate all its attention on the remaining clusters. This then makes it possible to obtain more beautiful clusters .
Very often, the wine producer harvests the greenest and least promising berries, to promote the maturation of the others.
This practice may seem surprising, especially when removing bunches that have not reached maturity. However, it is a method which ensures a certain consistency between the size of the vine and the number of fruits it bears. This then prevents it from bending under the weight of excess grapes, which could risk spoiling the entire vine stock.
It is also an excellent way to manage the yield of a vineyard , and thus to respect the rules of the specifications of certain appellations, for example.
Summer work: protecting fruit trees
As we saw above, for optimal growth and maturation of grapes, vineyards need a mild climate. But nothing guarantees the winegrower a calm and sunny summer, and he sometimes has to face capricious climatic conditions. Its role is then to protect its vines from these hazards.
Moreover, even with a stable climate, summer weather is conducive to the development of vine diseases . Indeed, heat and humidity encourage the growth and proliferation of pests and parasites, such as phylloxera , which wreaked havoc in the 19th century, and which is still feared by winegrowers. As for the rains, even if they are weak, they can give rise to diseases such as powdery mildew or mildew .
Wine producers must then take care to limit these risks, by using different remedies. Conventional viticulture vineyards then use phytosanitary products and chemicals , such as herbicides and pesticides. On the other hand, organic vineyards are not allowed to use this type of product, so they must use natural solutions , promoting the development of biodiversity. For example, installing nest boxes helps attract birds and bats, which will then regulate the presence of pest insects.
In the event of a proven disease in the vines, organic winegrowers can use copper, baking soda, sulfur, nettle manure or even garlic decoctions to get rid of it naturally.
Preparing for the end of summer harvest
All stages of work in the vineyard in summer lead towards the same objective: the harvest . The date of picking the bunches of grapes varies according to the wine-growing regions, and according to the specifications of the appellations. In certain geographical areas, such as Provence, the harvest can start at the end of August , while others wait until mid-September, or even the beginning of October for late harvests .
To define the harvest date , the winegrower relies on the level of maturity of the grapes, and also decides according to the wines they wish to produce.
In the cellars, everything is set up to accommodate the bunches of grapes and begin vinification of the wine.
Summer in the vineyards is the most intense period, and it is at this time that the winegrower's entire year is at stake. His vigilance and involvement are then at their peak. It is only after the harvest, at the beginning of autumn, that he will be able to take a little rest. A fairly short break, before preparing the vines for winter .