2019/2020 Nova Scotia Wine Grape Bud Hardiness Report no. 1: November 12 - 13

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.

Bud hardiness values are 2 °C to 3 °C higher compared with comparable dates in 2018. This is likely due to the delay in all of the grapevine phenological stages this year, from bloom through to harvest. This delay in bud acclimation does not appear to be a problem though, as temperatures for the end of October and early November have been near or slightly above the normal seasonal values. Figure 1 shows a 10 to 15 °C buffer between LTE 50 values and observed minimum temperatures. Short and medium term forecasts indicate that this temperature trend will continue for the next two weeks.