University of California
Central Sierra

Growing Wine Grapes

Understanding site "capacity": the key to farming grapes successfully in the foothills.

vinyardlandscapLC
Capacity is a term that refers to the productivity (growth) of the whole vine and includes the vigor-inducing potential of your site, combined with the growth properties of the variety and rootstock.  Vigor is defined as the rate of shoot growth, as measured by change in length over time. Grapevines are generally vigorous-growing plants, but there are many ways this vigor can be manipulated to create vine balance, given the inherent characteristics of the vineyard site.  Understanding your site capacity is the KEY to selecting the appropriate rootstock, variety, vine and row spacing, irrigation scheduling, and trellising type for YOUR parcel, allowing you to adjust growing parameters to work with your site capacity in order to achieve the desired vine balance.

Understanding the capacity of your site is the first step to achieving vine balance, quality grapes and quality wine!

Site capacity is mainly indicated by the soils on your site, and the site microclimate.

  • Remember, foothill grape growing sites are highly variable! Each parcel needs to be evaluated for its potential.
  • Soils can be deep and nutrient-rich, such as many volcanic soils, or more shallow, (say, at the top of a slope) or/and lacking some key nutrients, such as granitic soils typically low in phosphorus.
    • Micoclimates also vary greatly.
      Click image for a larger view.
      Click image for a larger view.
      Depending on elevation, but also slope and aspect can vary on a single parcel.  Weather conditions, particularly FROST (shown in the picture right)- which commonly occurs in the foothills both in spring and in fall, is a key consideration when selecting varieties and choosing your vineyard location.
  • Calculating the available irrigation water you will have (either well water or delivered), is also an important factor for planning your vineyard.
  • You'll need the ability to manage certain pests and disease problems, such as powdery mildew, which ALL grape growers must be prepared to spray
    vinesprayer
    for, in order to produce quality grapes without defects.
  • And, the ability to conduct cultural practices, such as grapevine pruning and training, leaf and shoot removal, and canopy management in a timely manner.
  • Finally, the ability to market your grape crop and receive a fair price, which requires not only growing an excellent product, but also developing a relationship with a buyer based on communication.

Information on upcoming workshops!

Webmaster Email: cecentralsierra@ucdavis.edu