Can be the single most important aspect of grape production in the new world, even if it is not always appreciated as such. If, for example, the new vineyard is in a cool region, then the topography of the site may be a critical factor in avoiding frost damage and the aspect chosen may be vital to ensure adequate warmth for ripening (see hillside vineyards). On the relatively rare occasions when a vineyard site may be selected in the Old World, it is, of course, just as crucial. (Most Old World vineyards have been in existence for centuries, and when a new vineyard is created, or recreated, another important consideration may be whether or not it qualifies for a certain appellation.)
Vineyard site selection embraces more than just choosing the vineyard location, as the decision will affect the vineyard’s yield, quality of the wine produced, and therefore the vineyard’s long-term profitability. The site’s regional climate, or macroclimate, for example, determines by virtue of temperature and sunshine hours which vine varieties should be grown, and the resulting likely wine style and quality. For example, lower temperatures produce more delicately flavoured wines, and hot climates produce wines relatively high in alcohol. Such effects are discussed under climate and wine quality. Vineyards are often planted at higher elevations to take advantage of lower temperatures. The site selection process might include evaluating climatic data from distinguished wine regions in an attempt to locate similar climates, or homoclimes, as has been done with considerable success in Australia. With its enormous range of latitude and elevation, Chile has a greater opportunity than most countries to match climates.
Modern science is creating new methods of vineyard site selection, especially based on geographical information systems (GIS) and digitized databases. Researchers at virginia tech in the US, for example, have identified sites with the greatest potential by overlaying maps of the same area according to different selection criteria such as elevation and land use, slope and aspect, and winter freeze risk. Such approaches provide a useful alternative to the trial and error more usually employed.
Similarly, rainfall and humidity affect the likelihood of many vine diseases, especially important fungal diseases such as powdery mildew, downy mildew, and botrytis bunch rot. The likelihood of these diseases can be estimated by reference to climate records. In addition, the threat of nematodes may be evaluated by knowledge of indigenous types, or of the previous crops grown on the site. It may even be possible to avoid the introduction of phylloxera and other pests and diseases by creating a local quarantine. If phylloxera and nematodes are considered a likely problem, the appropriate rootstocks can be used.
The site climate, or mesoclimate, affects, for example, the extent to which cold air drains away, and the likelihood of spring and autumn frost. A site’s proximity to bodies of water such as lakes (see lake effect) can be important in providing protection from injury due to particularly low temperatures, as in new york state and switzerland. These attributes depend on local topography.
The balance between rainfall and evaporation indicates the likelihood of drought, and for some regions at least whether irrigation is desirable, and the amount of water required. In many parts of the world availability of high-quality water for irrigation is an essential factor in site selection. This may involve locating vineyards near streams or rivers, or with access to underground (artesian) water, or opportunities to build dams or reservoirs.
soil conditions present at the site will determine vineyard vigour, with deep, fertile soils, for example, leading to vigorous growth and the possibility of high yields, but the concomitant need to manage the problems this creates (see canopy management). Premium-quality vineyards are typically found on soils with low water-holding capacity, and low soil fertility. Site selection normally involves a process of soil mapping and physical and chemical analysis of soil samples. This allows potential problems such as poor drainage or soil acidity to be treated appropriately before the vineyard is planted. Knowledge of soil depth indicates likely vine vigour.
Vegetation growing at the site, and the productivity and quality of other agricultural crops grown in the region, can be used as an indicator of the vineyard performance. The types of trees present give guidance as to the soil properties, and their size for their age indicates soil fertility and water supply.
Not all important features of potential vineyard sites are natural ones. Frontage to busy roads is essential if retail sales are expected from the vineyard site. Good communications with markets and proximity to a supply of labour can also be significant. The performance and reputation of other vineyards in the area can also be commercially important.