Issue link: http://winesandvines.uberflip.com/i/107279
GRAPEGROWING data. We make our model freely available to anyone who wants to use it and are currently working with scientists in other states—New York, Virginia, Idaho and Colorado as well as British Columbia— to test if it might be applicable under those different conditions. W&V: How can growers use pruning to mitigate frost damage? Keller: Pruning as late as possible is now standard industry practice. If you prune before a freeze event, you won't be able to compensate later. Growers can use our monitoring service or the model described before as a tool to decide where to evaluate bud or vine damage. For example, if the model predicts damage for some varieties but not others—or for some locations but not others—they can focus their attention to the trouble spots. They will then assess the percentage of dead buds following a cold event. Once they know how much damage they have, they will decide whether to use compensatory pruning or to retrain. With compensatory pruning, and depending on the level of damage, they will leave more buds (up to no pruning at all) to compensate for those that are dead. This way they can often get a consider- ably higher yield than if they simply used standard pruning practices. W&V: How about irrigation? Keller: Deficit irrigation has the added benefit of accelerating cold acclimation, thereby improving cold hardiness. However, the roots (especially of own-rooted vines) are very susceptible to cold temperatures, especially in dry soil. Roots of Vitis vinifera can get killed at 22°F (rootstocks are typically hardier), which is a real concern, especially in newly established vineyards. Therefore, growers withhold water in early fall to encourage shoot maturation, but then use irrigation at the end of the growing season to increase soil moisture in the root zone, which has an insulating effect. We also plant young vines fairly deep, down to 18 inches, which keeps the roots away from the cold topsoil. W&V: You've studied which grape varieties are the best for cold-hardiness in eastern Washington. Which are the best choices and why? Keller: This is a tricky question, as the industry wants to grow varieties that are in demand for quality wine, not varieties that are necessarily cold hardy—or else everyone would be growing hybrid grapes. There is no one "best" variety for these conditions. A variety can be very early to acclimate in fall, have good mid-winter hardiness, but break bud early, which makes it vulnerable to spring frosts. This is Chardonnay, our most widely planted white winegrape. And a variety that is hardy in mid-winter and spring can be a problem in the fall, because it does everything late. Cabernet Sauvignon, our most widely planted red winegrape, is such an example. It is not so much about what are the best choices as it is about avoiding really bad choices. We know, for instance, that some southern European varieties (such as Grenache, Mourvèdre and Sangiovese) tend to be less hardy than their northern European cousins. So I don't recommend these for vulnerable sites. A resident of the Santa Cruz Mountains, Laurie Daniel has been a journalist for more than 25 years. She has been writing about wine for publications for nearly 15 years and has been a Wines & Vines contributor since 2006. References 1. w ine.wsu.edu/research-extension/weather/ cold-hardiness 2. weather.wsu.edu/awn.php strategic capital and expertise for the wine industry www.bacchuswinefund.com (415) 828-8898 bacchuscapital@bacchuswinefund.com NATURALIST PARADISE 1100' East shore Cayuga Lake Plus; 159 Acres , +/- 80 Tillable Should be good for vinivera grapes. Truly a unique, pristine and private property in the Heart of the Finger Lakes. Property flanked by two streams, gulley. Victorian 5 bedroom, 1.5 baths. $1,499,000 Senecayuga Properties, LLC 97 Fall St., PO Box 386, Seneca Falls Mel Russo Licensed Real Estate Broker/Owner Office: 315-568-9404 • Cell: 315-246-3997 senecayuga@aol.com • www.senecayuga.com Win es & Vin es F EB RUA RY 20 13 61