Cold calculations

Brad Foster, an owner and vineyard manager for North Mountain Vineyard in Maurertown, walks through a row of cabernet franc grape vines outside the vineyard on Wednesday. Foster says there has been no cold weather damage to the vines so far this season, but area vineyard owners have expressed concerns. Experts say that 2015 damage should prove less than 2014. Rich Cooley/Daily

As the winter months draw to a close, vineyards in the Northern Shenandoah Valley are once again monitoring the weather for freezing temperatures.

In 2014, abnormally cold temperatures caused some area vineyards to lose vines and drastically affected operations.

Krista Jackson-Foster, co-owner of North Mountain Vineyard in Maurertown, noted that the temperatures have not been cold enough yet to cause serious damage.

The National Oceanic and Atmospheric Administration estimated that, for the month of February, temperatures have been nearly 7 degrees below average.

However, NOAA has also reported that temperatures in this region were half-of-a-degree below average in January and almost five degrees above average in December.

Effects from freezing temperatures are basically variable, according to Tony Wolf, viticulture specialist at the Alson H. Smith Jr. Agricultural Research and Extension Center in Winchester.

In order for freezing temperatures to cause “serious damage,” Jackson-Foster said it has get to “4 degrees below-zero for about four hours.”

Tyler Newcomb of Valerie Hill Vineyards said that some varieties of European vines can see damage as the temperatures drop below 10 degrees.

Wolf said, “That low temperature critical threshold is governed by how cold the preceding temperatures are leading up to the stress event.”

For example, Wolf noted that last week was actually “the best we could have hoped for” because the temperatures were “low, but not damaging.”

“This makes the plants a little more ‘cold hearty’ and … increases their ability to resist damage,” Wolf added.

Wolf also said, “We’re talking about a few degrees, but sometimes that is all that it takes … to mean the difference between some injury and no injury to the plant.”

Ron Schmidt, owner and operator of Cedar Creek Winery in Star Tannery, also said the weather has not been cold enough for serious damage to occur.

Jackson-Foster noted that, ironically, snow can actually provide natural protection for certain types of vines.

“We have a nice blanket of snow on our vineyards, and that covers the grass section … it’s like a little blanket,” she said.

The snow, Jackson-Foster added, provides a “slow melt,”  which benefits the soil and plants for the spring season.

Each owner agreed that younger vines are more susceptible to damage than seasoned vines during the winter.

Newcomb said that vineyards will continually prune plants throughout the winter months to prepare for the spring.

Jackson-Foster said that some vine damage is be to expected during the winter months.

“There are always a bunch of vines that do not make it through the winter,” she said, “We have to take out the damaged vines … and replant a new [vine] there.”

Newcomb said that the bigger concern for vineyards, in terms of freezing, is the hard frosting that can occasionally occur in the early spring months.

Wolf said, “The thing I’m a little worried about, is this pattern we have been in, this sort of roller coaster ride.”

Wolf said, temperatures in the 60s and 70s can cause vines to “lose their cold heartiness.” Temperature shifts between cold and warm, Wolf explained, can “lead to spring frost problems.”

Schmidt explained that he has been planting since 1999 and “lost total crops” in 2001 and 2013. This caused Schmidt and his operation to not produce any wine that year.

Newcomb noted, “Once you’ve got buds coming out of the vines, if you get a hard frost, it can kill those buds.”

The cost of the replacing vines, Newcomb said, can be between $10,000 and $12,000 per acre, depending on the variety. “If you lose an entire acre, then you have to replant that entire thing.”

Vineyard owners say they are monitoring the weather and hoping that temperatures do not reach extreme lows.

“We all worry about the same kind of things and we go through some scares with frost every season. It’s nothing new for our climate,” Wolf said. “We just have to deal with that.”

Wolf said that spring frosting for this season “is so far off that, at this point, I want to get through the winter first.”

Jackson-Foster noted, “We hold our breath during the winter months and say, ‘Hopefully we are not going to get a lot of damage.’ But there is nothing we can do.”

In regards to the 2015 winter season, Wolf said, “So far, knock on wood, things are looking fairly good.”

Contact staff writer Kevin Green at 540-465-5137 ext. 155, or kgreen@nvdaily.com