The apple and grape industries are not expected to experience too many problems with their crops following this year’s more mild winter.

Both apples and grape crops have ways to defend themselves from the cold during the winter months. During times when the weather gets dramatically warmer and then increasingly colder again this can present problems to the growth of each crop, but that has not happened so far this year.

“I don’t think it will be too bad this year,” Bill Meadows of Meadows Apple Farm in Forestville said. “We will find out in the spring.”

At Abers Acres in Kennedy, while they do not grow their own apples, they agreed that a more mild winter can often be more good than bad and that it is when it gets warm and then goes back to being cold that it often causes a problem.

Jennifer Phillips Russo, Team Leader and Viticulture Extension Specialist for the Lake Erie Regional Grape Program, said the idea is the same for grapes.

“Questions have been asked regarding how the milder winter may have affected grape crops,” Russo said. “I is important to stress that this year’s crop potential has already been determined in the vine’s compound buds set last growing season. Each fall, the green tissue that produced the grape clusters begins to harden off and get the woody appearance, or periderm formation. The vine slowly dehydrates to prepare for dormancy. This is when the grapevine transitions to a cold-hardy state to survive the winter temperatures, and it is called cold acclimation.”

Russo said that the grapevine responds to low temperatures and decreasing day length in a gradual process. As the temperature continues to decrease as winter approaches, the grapevine slowly acclimates to those seasonal temperatures and gains cold hardiness. This process can depend on many factors, including the type of grape, its genetic makeup, seasonal temperatures and how they vary, and the condition the vine is in when it enters its dormant season. If a grape vine enters the winter stressed from disease then it may not be as hardy as a healthy, balanced vine.

“The fact that we have had milder winter temperatures connects to the grapevine’s maximum cold hardiness,” Russo said. “For example, if our winter temperatures were gradually decreasing to below zero, the grapevine cold hardiness would be acclimated to those temperatures and able to withstand colder temps, conversely, if the winter lows never dropped below 25 degrees Fahrenheit, then they would experience damage if all of a sudden a subzero front hit because they would not be acclimated to those subzero temperatures.”

Grape vines reach the maximum cold hardiness around mid January or mid February. Then as temperatures begin to go back to being milder, the vines begin to wake up.

“It is the reverse of the acclimation process,” Russo said. “Warmer temperatures gradually wake up the dormant vine and the tissue gains water or rehydrates. As soils warm up, capillary action draws water up the trunk, and ‘sap flow’ occurs.”

The vine continues to rehydrate through the bud swell, which is when lower temperatures become a concern, due to the potential for the water inside the tissue to freeze. Freeze injury can typically happen to the primary bud, but Russo said she has yet to see that this season.

So far this year, Russo said the milder winter has not led to cause for concern for grape bud cold hardiness, but may lead to other problems like trunk splitting.

“There is potential for trunk splitting should we experience an extreme drop in temperature in a short amount of time,” Russo said. “The sap flow could potentially freeze in the trunk, expand, and cause damage. We have not recently endured that scenario across the region to cause worry — such as the extreme drop around Dec. 25 –, however, should you find evidence of it please contact me so we can track it.”