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College of Food, Agricultural, and Environmental Sciences


2023 Year in Review

Monday, January 08th, 2024

By Imed Dami and Diane Kinney, HCS-OSU

This article summarizes the 2023 dormant and growing seasons and the impact of weather on grape varieties grown on the research vineyard at the OSU-OARDC in Wooster, Ohio.

Weather: Temperature

Our 2023 growing season was greatly affected by a freeze event on December 23, 2022 to -7 F. Bud injury was higher than normal due to warmer (3F) than a typical December. The early part of the year was significantly warmer than both the long-term average and 2022 temps. This did not hold true for the early growing season though as temperatures were below in both areas. In Wooster, we missed a frost event in mid-May that greatly affected other grape growing regions in the state. Our last date for temperatures below freezing in the spring was April 27th which coincided with bud break. Phenological progress was slow due to cool, dry temperatures. During fruit ripening in early fall, temperatures followed closely to both long-term and 2022. Cumulatively, as year end, we are only slightly above 2022. We did have an earlier fall frost date of October 31st resulting in a lower-than-average FFD of just 187 in comparison to 201 in 2022.

Weather: GDD

Nearly 40 GDD units were gained during early winter from the 1st of January through 1st of April. April continued to be slightly above both 2022 and the long-term averages but things drastically dropped off for the entire growing season May through September. By years’ end, we are at only 2734 GDD vs 3104 in 2022 which was already significantly lower than 2021. In relation to the long-term 30-year average of 3058 GDD, we are 324 GDD lower at this time. This is the first time that yearly GDD dropped below 3000 in 10 years.

Weather: Precipitation

Annual precipitation was above the long-term average but significantly below 2022 (34.53” vs 41.03”). That being said, we did have near drought like conditions during the early growing season mid-May through mid-June with nearly no rainfall at all. This early drought ended with nearly 3” the last two weeks of June alone. July and September were also very dry. A 5-day period in early August recorded 2.69” with another near 3” the last week of the month. In September, we only recorded 0.32” with November at 1.36”. In general, and except August, we had a drier than normal summer-fall, which impacted disease pressure in 2023.

Vineyard Notes:

2023 Winter freeze injury:  The deep freeze of December 23, 2023 caused significant bud injury. Vinifera varieties (15) sustained 85-100% primary bud injury; Table grapes (8): 55-100%; hybrids (19): 15-82%. The causal claims, that the temperature dropped very fast, are not accurate. In our vineyard, temperature dropped about 50F in 24 hrs or 2F/hr. That is considered a normal “freezing rate”. It is the mild December that led to “deacclimation” of vines. Also, the freeze-thaw cycle (45F/-7F) just before the event exacerbated the extent of damage. However, the crop loss in some varieties was not as severe as expected due to our pruning adjustment. For example, Chardonnay sustained 85% bud injury but produced 3 tons/acre after hedge (or minimal) pruning.

Diseases and insects: With the drier weather, diseases were also less of a problem this year. Bird and racoon damage was nearly non-existent, but yellow jacket damage was fair which led to high sour rot incidence. Dr. Ivey confirmed a new disease, called ripe rot, for the first time in Ohio that we found in some of the varieties in Wooster. More information regarding this will be shared at a later time.

Fruit quality:  Sour rot continues to be our biggest challenge in fruit quality. Harvest began on August 23rd for Briana and our final harvest occurred on October 5th for Cabernet franc. Despite a very low GDD, we were able to ripen fruit of most varieties and fruit composition was appropriate. For example, in 2023, sugars in 14 varieties averaged 19.9 Brix. In 2022, the average was almost the same at 19.8 Brix. Acidity was also below 10g/L in general despite a cool season. TA averaged 7.5 g/L in 2023 and 7.9 g/L in 2022. It is possible that fruit chemistry was not impacted negatively (based on low GDD), because we had a low crop load due to winter injury. So there was less fruit to ripen in most varieties. We also like to think that our group did a good job with canopy management that enhanced fruit quality even in a cool year!

Table: 2023 Harvest fruit composition of selected grape varieties at the Wooster research vineyard: (2022 data)



January 8, 2024 - 4:15pm --