Things are Heating Up!

Although January and February were mild months across apple growing regions in Ontario (Figure 1), there was a slow progression of growing degree days (GDD). Things of note from Figure 1:

• January & February of 2023 has followed a similar pattern as 2020
• January & February of 2023 in Harrow and Vineland have been more mild in comparison to 2020, while other locations were comparable
• January & February of 2023 has been milder than the 5 and 10-year average temperatures

Across the province, temperatures of March 2023 were similar to 5 and 10-year averages but were more mild (Figure 2). When comparing March of 2023 to 2020 average temperatures, 2023 was a few degrees cooler, aligning with the delay in growth staging.

Recently spring has sprung into action and things are pushing along quickly! The forecast shows steady warm days in the coming weeks as well. Expect buds to break – if they haven’t already – across various regions of the province.

As of April 11 2023, these are where apples stand across the province:

County	Growth Stage
Chatham-Kent County	Dormant, silver tip and bud break
Waterloo County	Dormant
York County	Dormant and silver tip
Durham County	Dormant and silver tip
Grey County	Dormant
Elgin County	Green Tip
Essex County	Green tip on Gala and McIntosh, Silver tip for other varieties
Lambton County	Green tip on Gala Green tip on Gingergold & Paula Red for a week
Durham County	Dormant and silver tip
Wentworth County	Silver tip

In Simcoe, some photos associated with staging is below:

• Ambrosia, Dormant, April 6 2023
• Gala, Silver tip, April 6 2023
• Gingergold, Green tip, almost half-inch green, April 11 2023
• Honeycrisp, Silver tip, April 6 2023

When looking at GDD accumulation, various apple growing locations across the province are below (Figures 3 to 13). General comments are below:

• We are at Julian Day 100 as of April 10, 2023
• Average bud break over the past 10 years for McIntosh in the Simcoe area is Julian Day 107 (April 17, 2023)
• 2023 has been slow for GDD accumulation, falling below 5 and 10-year averages
• 2023 continues to follow a similar path as 2020, except for Vineland, where 2023 follows the 5 and 10-year averages

I will continue to update on growth staging, GDD and weather as the season progresses.

If you would like any additional information, have suggestions, or would want to see data from a location closer to you, please contact Erika DeBrouwer via email or phone (erika.debrouwer@ontario.ca, 226-931-4098).