Good morning everyone. We are in that time of the year in which we count our chill hours/portions accumulated during the season. As a refreshment, we have multiple sources of information that can be used. Please refer to our previous post https://site.extension.uga.edu/peaches/2025/01/chill-data-sites-and-new-tools-for-dynamic-model-data/ for more detail information of what sources can be found out there to determine your current chill.
So here is our situation as of now with our major models
| Chilling Hours Under 45 ℉ (Weinberger model) | |||||||
| Station Name | 2024 TO 2025 | 2023 TO 2024 | 2022 TO 2023 | 2021 TO 2022 | 2020 TO 2021 | 2019 TO 2020 | 2018 TO 2019 |
| Attapulgus | 692 | 566 | 457 | 620 | 626 | 469 | 571 |
| Butler | 807 | 747 | 642 | 750 | 825 | 711 | 781 |
| Byron | 851 | 817 | 669 | 835 | 867 | 783 | 817 |
| Fort Valley | 854 | 794 | 676 | 813 | 855 | 787 | 832 |
| Chilling Hours Between 32 ℉ and 45 ℉ (Modified Weinberger model) | ||||||||
| Station Name | 2024 TO 2025 | 2023 TO 2024 | 2022 TO 2023 | 2021 TO 2022 | 2020 TO 2021 | 2019 TO 2020 | 2018 TO 2019 | |
| Attapulgus | 545 | 498 | 361 | 573 | 539 | 439 | 529 | |
| Butler | 624 | 645 | 535 | 673 | 725 | 649 | 704 | |
| Byron | 625 | 665 | 534 | 728 | 716 | 714 | 719 | |
| Fort Valley | 618 | 641 | 542 | 724 | 702 | 719 | 705 |
| Chilling portions (Dynamic model) | |||||||
| Location | 2024 TO 2025 | 2023 TO 2024 | 2022 TO 2023 | 2021 TO 2022 | 2020 TO 2021 | 2019 TO 2020 | 2018 TO 2019 |
| Attapulgus | 35 | 45 | 33 | 40 | 43 | 42 | 40 |
| Butler | 49 | 57 | 46 | 54 | 59 | 60 | 65 |
| Byron | 52 | 57 | 47 | 55 | 62 | 62 | 66 |
| Fort Valley | 52 | 57 | 46 | 59 | 60 | 65 | 54 |
For chill portion data accumulation, we are down from last year for the middle GA area. It is quite similar to 2022 to 2023 season. In this season, we had lack of chill symptoms in our high chill material, however, we also observed an early bloom in our lower chill material, which resulted in high loss due to a freeze. In the 2023, we lost about 80-90% of our crop.
To have a potentially good crop – at the minimum – by Feb 15th varieties requiring (modified from Dr. Reighard)
- 650 chill hours need ~ 30-35 Chill portions
- 750 chill hours need ~ 35-40 Chill portions
- 800 chill hours need ~ 40-45 Chill portions
- 850 chill hours need ~ 45-50 Chill portions
- 950 chill hours need ~ 50-55 Chill portions
Currently, we are in 49-50 chill portions in middle GA. We are quite similar to 2023 season. Based on my notes, the 2023 season was characterized by prolonged bloom in high chill cultivars. At this point, we are probably going to see issues with specific variety(ies) that have been presenting issues last seasons (high chill), with either delayed or extended bloom. We probably have gotten all the chill that we were going to receive for this season.
Finally, we added a new feature, a winter feature, to the smartirrigation peach app (https://smartirrigationapps.org/peach-app/) developed by our program. The app can be downloaded in Android and in Apple devices. The app will provide data on chill accumulation for fields created within the app for Florida and/or Georgia. Models supported by the app are the Weinberger, the Modified Weinberger, and the Dynamic models. The app uses data from weather stations located close to the farms created by the users. If you are new to the app, first you will need to create a field(s). There is a step-by-step video on the website described above. Once you have created your fields you will be able to see the chill accumulation at each farm. You can then click on the farm and will be able to access a graphical representation of the chill accumulation. In this window, you can click on the models and easily switch between the different models. Here are some pics of the app.
Please if you have any questions, comments, and suggestions, or if you would like to have a conversation about our current situation please feel free to contact me at 352-871-3981 or dchavez@uga.edu.
