The study and recording of terrain, elevation and land features is known as topography. A potential site for a vineyard should be evaluated heavily on the basis of its topography. It’s not enough to know the general characteristics of an area being considered for vine planting. One must consider the consequences of minor attributes and changes in vineyard topography before any land is committed to vine growing.

Perhaps the most important feature of any vineyard site is the elevation. The height (above sea level) at which the grapevines are planted has a tremendous impact on the temperatures that the vines will have to endure. On average, temperatures decrease 3.5 degrees F for every 1,000 feet above sea level. With frost being a major enemy of grapevines, the temperatures for a given site must be calculated with great precision. Even one or two degrees can make the difference between extensive damage to the vines and fruit and producing a healthy crop. 

Most vineyards are planted on sloping hillsides. This allows the cold air to flow downhill and forces the warmer air up the sloping terrain. A prospective site should be free of depressions in the slope, called frost pockets. These pockets are where cold air collects and becomes stagnant. Frost pockets are often accompanied by fog, so they are rather easy to identify. It’s still very possible to plant a vineyard on a hillside with one or more frost pockets, but the vines themselves should not be planted near the pockets, as they will likely suffer the colder temperatures.

A vineyard’s aspect refers to the direction that the slope faces. In North America, most vines are planted on south-facing slopes, allowing the plants to soak up more of the sun’s rays. Western slopes are also a popular choice, as they provide the vines with warmer temperatures later in the day. However, eastern-facing slopes promote early-morning frost and mildew protection, because the grapes tend to dry out sooner from the early sun exposure. Some grapes benefit more from early sun, and some seem to prosper more with late afternoon sun. The aspect of the vineyard can also affect the timing of budbreak, veraison and harvest. One should consider the traits and needs of the specific grapes being grown before choosing an aspect for the vineyard. 

Having at least a slight slope of the land is essential to the success of most vineyards. As mentioned earlier, the slope allows the cold air to flow downhill, providing frost protection. A slope of at least 5 percent is usually recommended for most vineyards, with 10 to 15 percent usually being optimal. Some vineyards definitely reside on a greater slope than this, but steeper slopes provide greater challenges where machinery and harvest are concerned. The slope of a vineyard also has an effect on water drainage, which is vital to vineyard success in most regions.