2026 Spring Freeze Updates and Guidance

By: Maria Smith, HCS-OSU

2026 has been a long year, and yet it is only May. All of our fortitude is being tested, whether that is in the form of waiting out the winter polar vortex in January for the hope of primary or secondary buds to emerge this spring, or now, waiting out for any secondary buds to emerge following the past two weeks of sub-freezing temperatures with the growing season underway.   

This post serves as an update to the status at Hort Unit 2 and observations from around the state with the past two weeks of spring freeze events. 

It has barely been 4 weeks since we wrapped pruning at Hort Unit 2 in Wooster, and in that time, we have completed the following tasks:

• Removing our soil hills for graft union protection in Vinifera varieties
• Removing old vines for replanting
• Applying a post-emergent herbicide application of Forfeit 280 – we will be planting new vines at Hort Unit 2 and do not want to interfere with establishment from pre-emergent herbicides 
• Applying a dormant application of Sulforix (sulfur-lime) following a difficult 2025 season with Phomopsis

The growing season in Wooster officially kicked off with 50% budbreak reached between April 13 – April 17 (Figure 1). For reference, this is nearly 8 to 10 days earlier than 2025 (April 21 – 23). Effectively, all cultivars broke bud around the same day this year, which deviates from our typical notion of a stratified bud break (“Early” vs. “Late”) across grape species and cultivars. However, there are still noticeable differences in developmental rates. 

Rapid onset of growth the past few weeks was pushed by unseasonably warm April temperatures, which exceeded average daily temperatures from +3 to 7 F (Figure 2). Within the two-week period preceding budbreak, cumulative growing degree days (GDD; a measure of heat accumulation used for estimating plant phenological development = [(Daily max + Daily min)/2] – base 50F) were between 108 (April 1-April 13) to 186 (April 1 – April 17) for Wooster. 

Figure 1. Chambourcin (top), Marquette (center), and Cabernet Franc (bottom) at Hort Unit 2, Wooster from 16 April 2026.

Figure 2. Mean temperature deviation for April 2026 (figure from climate.osu.edu)

This is now the 2^nd year in recent memory (the other being 2024), where we were this early in phenological development. The problem, however, is that the median date of last freeze (28 F) remains the same (with latest dates being May 1 – May 15; Figure 3). Looking back into the OGEN archives, we have posted about the risk for spring freeze injury every single year dating back to my first spring at OSU in 2019 (7 years, for those counting). While this is clearly not a novel issue, what is novel is how early development is occurring. It’s not a couple of days, it’s weeks. 

Figure 3. Median date of last 28 F (figure from mrcc.purdue.edu). 

Freeze events 4/20 – 5/3

Temperatures have reached 32 F or below across different portions of Ohio for 4 nights over the past 2 weeks, April 20, April 21, May 2, and May 3 (Figure 4).

Figure 4. Minimum temperatures for 4/20-4/21 and 5/2-5/3. Figures from mrcc.purdue.edu. 

At Hort Unit 2, minimum temperatures reached 29 F on April 20 and 21 and 35 F on May 2 and 3. While there was damage (Figure 5), the severity was very dependent on variety and location in the vineyard. We currently estimate anywhere between < 10% to as much as 50-60% primary shoot injury. 

Figure 6. Shoot damage varied based on variety and location at Hort Unit 2 (Chambourcin - top, Marquette - center, Cabernet Franc - bottom – 21 April 2026). Shoots will take on a dark green, wilted and “wet” appearance immediately following injury and will “crisp” over the next day or so.  

Thus far, most of the state has been spared significant injury over the past few weeks with damage limited to cultivars at more advanced phenological development or those that are in lower-elevational portions of sites. However, in Central and Southern, OH the damage was far more severe following the freezes from this past weekend (5/3) in part due to the advancement of shoot development over the past two weeks (Figure 5). Weather from newa.cornell.edu suggested regional temperatures between 29 to 33, depending on site-specific conditions in Central and Southeast Ohio, where most damage was reported. 

Figure 6. Shoot damage in Aromella in Lancaster, OH following below freezing temperatures on 3 May 2026. Photo used with permission from K. Salyers.

Spring Frost FAQs

Over the years, we (OSU) and our regional colleagues have put out guidance following spring freeze events. The most recent guidance can be found in the following resources:

1. Dami and Smith. Managing injured vines after frost – May 2023. OSU Viticulture Extension. https://ohiograpeweb.cfaes.ohio-state.edu/blog/may-1-2023-247pm/managing-injured-vines-after-frost-may-2023
2. Harner. Post-freeze (4/21) Considerations. VT Viticulture Extension Program. https://vtviticulture.com/2026/04/25/post-freeze-4-21-considerations/
3. Fiola. Grapevine Frost Damage II: Compensation, Management, and Potential Options. https://extension.umd.edu/resource/grapevine-frost-damage-ii-compensation-management-and-potential-options/

There are a few items that I want to highlight from this information from which I frequently receive questions.

1. It is not always a given that a shoot is damaged beyond superficial injury. We earnestly experienced this with our Marquette. Even at 29 F across 2 days, our damage turned out to be relatively superficial, with shoots continuing to grow! We will wait to see how the flowers were impacted as bloom approaches in the coming month (Figure 7).  
2. No need to spend the time removing dead shoots. They will shed off with time and emergence of secondary shoots. 
3. Vines don’t typically die from spring freeze unless the temperatures are low enough to sustain vascular injury to trunks and cordons. 
4. Some management issues you can expect, include 
   1. Asynchronous fruit ripening if only a percentage of primary shoots were lost
   2. Ripening delays from secondary shoot development
   3. Higher rates of vegetative growth from crop loss
5. Yield loss expectations vary based on cultivar. Vinifera tend to have much lower fruitfulness on secondary shoots while many French American and cold-hardy hybrids have more fruitful secondary shoots 

Remember that grapevines are perennial and continuing to manage appropriately for pests, diseases, weeds, and nutrition is critical to maintaining the long-term health of the vines. 

Lastly, spring freeze is an active area of research for us in the Eastern US. We would like to hear from you if you experienced spring freeze injury over the past several weeks. A survey was put forth by our colleague, Jennifer Phillips Russo at Cornell University. If you would like to participate by sharing or updating your information, you can do so at https://cornell.ca1.qualtrics.com/jfe/form/SV_3so5iJNL5LCi13E.

Figure 7. Marquette at Hort Unit 2 with superficial freeze damage but shoot tips continue growth. 27 April 2026.