2018/2019 Nova Scotia Wine Grape Bud Hardiness Report no. 14: April 29 – 30


2018/2019 Nova Scotia Wine Grape Bud Hardiness Report no. 14: April 29 – 30


A wine grape bud hardiness report is generated and distributed to the Grape Growers of Nova Scotia (GGANS) membership on a bi-weekly basis throughout the dormant season. The bi-weekly survey is performed on 3 vinifera cultivars (‘Chardonnay’, ‘Riesling’, ‘Pinot Noir’) and 2 hybrid cultivars (‘L’Acadie Blanc’, ‘Marquette’) and involves 10 grower collaborators for a total of 23 varietal blocks in total. Each report uses a table to show the latest low temperature exotherm (LTE) levels for the present and past weeks. The report also includes comments highlighting observations over the last reporting period, a plot showing the change in LTE values throughout the season, the historical 100 year minimum values and the present year’s minimum values. Three times throughout the season (early, middle, late) 11 “extra” varieties (‘Baco Noir’, ‘Chenin Blanc’, ‘Geisenheim’, ‘Leon Millot’, ‘Lucie Kuhlman’, ‘New York Muscat’, ‘Pinot Gris’, ‘Sauvignon Blanc’, ‘Seyval Blanc’, ‘Seyval Blanc’, ‘Vidal Blanc’, ‘Ortega’) from 22 additional varietal blocks are also reported.

Large shifts have been underway in the bud acclimation values for all of the varieties in our survey. Most varieties have LTE50 values of approximately -15 °C, which is a net change of 10 to 15 degrees from their deep winter values. In spite of the changes, there remains a significant margin of safety between observed temperatures and the estimated bud hardiness. The lowest observed temperature in Kentville over the last 2 weeks was -2.9 °C on April 18th while the LTE10 values are estimated to be in the -12 °C range. On April 29th and 30th we took our last bud samples from commercial vineyards for this year. We would like to thank all of those who have delayed pruning to give us the source of buds that we need to produce the bud-hardiness estimates. Certainly none of this would have been possible without the collaboration and cooperation of the Nova Scotia Grape Growers.

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