How do I know which grape varieties are suitable for my climate?

The climate. In order for the grape to reach the desired perfection and harmony in order to produce a quality product from it, as a rule an optimum climate is necessary. However, this is not easy, because, among other reasons, the ratio of climate to yield quality differs for all grape varieties. The climatic conditions as a result of the meteorological and geographic elements of a site are difficult to predict. Moreover, it is unlikely that certain climatic conditions will repeat in the same form in time and space. In this respect, relations between the characteristics of the environment (medium) and some characteristic values of product quality have been sought, which has led to a large number of (bio) climatic indicators used to determine the properties of winegrowing areas. This generally led to the knowledge and assessment of the necessary prerequisites for good ripening of the grapes.

Energy and temperature. The vine has a high demand for solar radiation and its photosynthesis performance increases with the wavelength of the visible spectrum. Under warmly adequate conditions, the optimum is between 30,000 and 60,000 lux (1,000 W / m2 = 96,000 lux); With values above 30 ° C and 100,000 lux, the stomata of the plants are closed. The intensity of the photosynthesis and thus the growth of the shoot is closely linked to the development of the temperature; the maximum is 25-30 ° C. The rate of growth also coincides with the photoperiod, and it increases when the duration of the day reaches thirteen hours. A higher light intensity (up to a certain limit) promotes the growth and maturity of the grapes.

Light and temperature play a crucial role in fertilization by improving the differentiation process of inflorescences. Particularly at temperatures of 20-25 ° C and dryness, the flower is favored. Again cool and wet weather is detrimental, these are conditions that lead to poor fertilization. The temperature and light intensity promote the growth and maturity of the berries by increasing the photosynthesis activity and thus promoting the formation of sugars, the synthesis of the dyes and the aromatic components and ultimately the degradation of the acid. The asynchronous development of berries and grapes is often the result of their different exposure, which results in too little formation of dry substance and polyphenol with stronger shading. An air temperature of 10 ° C is considered the vegetation zero point of the vine. The eye activity begins in the spring as soon as the air reaches this temperature, and ends in October when the temperature falls below 10 ° C. Nevertheless, depending on the grape variety and cultivated area, the shoot begins at temperatures between 9 ° C and 13-14 ° C. This means that the activity of the root system starts earlier and ends later, since a soil temperature of 10 ° C is reached in the spring before and is longer in autumn.

The precipitation in the form of rain is of great importance for the development of the vine, because it affects the decisive quantity and quality of the grapes. In conjunction with temperature and soil moisture, it determines the water availability of the plant; Thus there is an interaction between climate and soil. The demand for water depends on the quantitative and qualitative objective of production. Traditionally, an additional irrigation is considered to be advantageous if the total water supply is below 360 mm in the vegetation phase and is considered unnecessary if the feed is over 500 mm. It can be assumed that a vineyard from the shoot to the maturity needs 300-500 mm of rain and 250-700 liters of water for the production of one kilo of dry substance. This adds up to a total of 700-1000 liters per vine. Drying phases reduce growth and yield. Summer heat shortens the ripening season, reduces acidity, color intensity, sugar production and promotes dehydration. Excessive rain, on the other hand, can cause damage such as infections with pathogens (peronospora and botritis), soil erosion, the dying of roots in case of a lack of drainage, or the drought of the flowers and bursting of the berries in the ripening phase.

Other climate factors. Among the many meteorological phenomena related to viticulture are the relative humidity, the wind and the hail.

Evapotranspiration and moisture deficit. Evapotranspiration potential (ETP) occupies an important place in climate analysis, since it is the element which, together with the precipitation, determines moisture deficit and excess. In order to produce the "hydrological balance", we must calculate the precipitation deficit as the sum of the positive differences between ETP and precipitation quantity. This index is very important from the point of view of viticulture, as different varieties, such as the duration of the vegetation period, affect the quality of the grapes.Evapotranspiration and moisture deficit. Evapotranspiration potential (ETP) occupies an important place in climate analysis, since it is the element which, together with the precipitation, determines moisture deficit and excess. In order to produce the "hydrological balance", we must calculate the precipitation deficit as the sum of the positive differences between ETP and precipitation quantity. This index is very important from the point of view of viticulture, as different varieties, such as the duration of the vegetation period, affect the quality of the grapes.