2021 Year in Review

By: Imed Dami and Diane Kinney, HCS-OSU

This article summarizes the 2021 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 weather trends for 2021 were nearly identical during January and March to 2020 with very warm temperatures.  We had a slight drop during February with a recorded low in Wooster of -2.4 oF on the 17th.  That was our lowest temperature for the winter months.  We were fortunate to avoid any spring frost events. Temperatures during the ripening period of August through October remained above the long-term average. October temperature was nearly 8F above average, which was ideal for fruit ripening. The fall killing frost occurred on November 3rd in Wooster. The year ended with nearly 10F above normal in December which is not ideal for vine cold acclimation.

Weather:  GDD

In comparison with 2020, although our average daily temperature was about 8 degrees warmer in January for 2021, we did not gain any GDDs until March.  But we doubled the average that single month.   In October, GDD (300) were more than double the 30-year average. Warm temperatures during the ripening season pushed us well above both 2020 (3000 GDD) and the 30-year average (3063 GDD) ending with 3295 GDD. 

Weather:  Precipitation

2021 ended with a total cumulative rainfall of only 30.99”.  Rainfall was below normal in 8 out of the 12 months, especially in the winter and spring months. The trend in the downward direction has continued over the past 4 years, which may be an indicator of drought cycle in Ohio that may linger for a period of time. July was the wettest month with 6.75”.  The ripening period was relatively dry which helped keep the fruit clean.

Vineyard Notes:

2021 Spring freeze injury:  Once again, we dodged the spring frost bullet in Wooster.   This was a very good thing as the warm temperatures in mid-March (low 60’s on March 24th) found bud swell occurring earlier than we would hope.  Thankfully, the temps dropped at the end of March and early April to slow growth down a bit.

Diseases and insects:  Our biggest enemy this year by far was a larger than normal population of bald faced hornets, yellow jackets and honey bees. We did observe some Downy Mildew in susceptible varieties.  The dry spring and early ripening period allowed for a clean fruit at harvest  Little damage occurred from wildlife this year which is dramatically different from past years.

Fruit quality: The dry/warm weather in August and September helped our fruit develop quickly with our first harvest being on August 23rd. After an initial burst, fruit ripening slowed to a more manageable  harvest schedule ending on October 19th. Crop yields were high in most varieties. In general, berry weights and sugars were higher and acid was lower than in 2020, an indication of more ripe fruit for 2021 vintage.

2021 Harvest fruit composition of selected grape varieties at the Wooster research vineyard: