Cold Hardiness of Grapevines Sustainable Winegrowing

There are three levels of cold hardiness in grapes and understanding these can help growers select and manage the best varieties for their region. Imed Dami, Professor of Viticulture in the Department of Horticulture and Crop Science at The Ohio State University, explains cold tolerance and new information about the role of abscisic acid in ripening.
First an overview of cold hardiness. The first level is very cold tender. A lot of these varieties are grown in California and they are not native to North America. Second, are cold hardy, or tolerant grapes. These are the native species to North America. And third are hybrid crosses. The majority of grapes being farmed fall into this category.
New research is being done on abscisic acid, a plant hormone that induces dormancy. When sprayed around version, it can help send the plants into dormancy earlier and maintain a deeper dormancy which makes the grapevines more cold tolerant.  
References: 2022-06-03 Roller Crimper Tailgate (Register) Abscisic Acid and Cold Hardiness in Grapes Buckeye Appellation Foliar Applied Abscisic Acid Increases ‘Chardonnay’ Grapevine Bud Freezing Tolerance during Autumn Cold Acclimation Foliar Application of Abscisic Acid Increases Freezing Tolerance of Field-grown Vitis vinifera Cabernet franc Grapevines (Abstract only) Imed Dami (email) SIP Certified Sustainable Ag Expo November 14-16, 2022 Winter Injury to Grapevines and Methods of Protection Get More Subscribe wherever you listen so you never miss an episode on the latest science and research with the Sustainable Winegrowing Podcast. Since 1994, Vineyard Team has been your resource for workshops and field demonstrations, research, and events dedicated to the stewardship of our natural resources.
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Transcript Craig Macmillan  0:00 
Our guest today is Imed Dami. He's Professor of Viticulture in the Department of Horticulture and Crop Science at The Ohio State University. Thanks for being on the show, Imed. So you're doing some pretty interesting work there in the Midwest or East, depending on who you ask. So you work in Ohio, and you work in cold hardiness of grapes, grape vines, which is the work you've been doing for quite a fair amount of time. Now, you did that as well, in your graduate work. What can you tell us about what the climatic conditions are like in Ohio, especially in regards to cold weather, that may not be seen another grape growing region to the US. So other listeners may not be familiar with kind of the challenges there are.
 
Imed Dami  0:35 
So in terms of the growing season in Ohio, it could be similar to many other grape growing regions in the country. However, during the dormant season, in the winter, it is different, it is much colder in Ohio. So the way we determine you know, how cold it is, in Ohio, is there is this maps, it's called the plant called hardness map developed by USDA. And these maps are based on lowest temperature for 30 years during the coldest month of the year. So they put that information together, you know, and they come up with averages, and then they divide, you know, each state into different zones based on those minimum temperature. Okay. So for example, in Ohio, we have three zone. The minimum temperature range between zero and minus 15 fahrenheit. So that is cold. And then they designate you know, these zones, like a number and the letter. So, for example, in Ohio, we have the three zones, you know, designated as six B, six A and five B. However, the majority of the state falls in the what we call six A's zone, where temps range between minus five to minus 15. So that is very cold. So, how do we relate this to the grapes? Grape vines, typically, they start to see cold damage at temperature of zero fahrenheit, or lower. So you could see, you know, like grown grapes in the majority of the location in Ohio is challenging, you know, just because of how cold it gets during the winter. Just to