CLEMSON, S.C. — Clemson researchers report South Carolina peaches and other fruit crops appear to have survived the recent cold snap, but only time will tell.
Temperatures fell as low as 19 degrees in orchards early Sunday morning, March 13. Clemson Cooperative Extension Service commercial fruit and vegetable agent Andy Rollins said the peach crop was in pink to full bloom stage when the icy temps hit. Rollins and other Clemson Extension agents spent all weekend working with growers to help protect their crops.
“Farmers spent last week preparing for the freeze event,” Rollins said. “Winds came in earlier than expected with near-freezing temperatures at 5 p.m. Saturday.”
Wind machines were used in some orchards. During cold, still nights, wind machines can be used to stir warm air above an orchard driving the warm air back down into the orchard, helping raise the temperature to potentially avert freeze damage.
“We started around 11:30 p.m. Saturday while others started earlier at 10 p.m.,” Rollins said. “As soon as the sun went down, temperatures dropped. Blooms from those orchards where wind machines were used look better than those not protected but temperatures were so low we’re not sure how much damage was done.”
Rollins will be looking at crops in his area to assess damages, but said peaches appear to be okay.
“This was quite the event,” Rollins said. “Thankfully, we’re still finding plenty of peaches. At those temperatures they really shouldn’t have survived so well. Every farmer I’ve spoken with is thankful for how little damage was done.”
The peach industry is a major contributor to the South Carolina economy. Figures from the United States Department of Agriculture show 84,000 tons of peaches were produced in the state in 2021.
Clemson Extension specialists are traveling the state assessing damages related to the recent freeze event.
Strawberries and blueberries on the Coast
Strawberry and blueberry crops in the Coastal Region also felt the cold blast. Rob Last, Clemson Extension horticultural agent, said temperatures dropped to 23 degrees with wind speeds of 15-to-20 miles-per-hour.
“Freezing temperatures started by 9 p.m. Saturday and lasted until mid-morning Sunday,” Last said. “Overnight lows hit 29 degrees with much higher humidity and lower wind speeds.”
Wind gusts may have done more damage than the cold. Zack Snipes, Clemson Extension horticulture program assistant team leader, said wind gusts hit 50 miles-per-hour in some places, ripping off row covers on strawberries, as well as plastic in fields and on greenhouses.
“Overall, I believe the strawberry crop pulled through fine where folks used and kept row covers down,” he said. “Blueberries got hit hard. The rabbiteyes were in full bloom and the highbush had lots of berries on them. I expect 50% losses or more in highbush and more in rabbiteye varieties.”
Snipes said it is “imperative we do a good job cleaning up with sanitation and using both protective and systemic fungicides after this cold and wind.”
Damage assessments will be made this week.
Brassicas and strawberries in the Midlands
In the Midlands, Justin Ballew, Clemson Extension commercial horticulture agent, said temperatures just east of Newberry reached 19.4 degrees Sunday morning, so some damage to strawberries is expected in that area. Brassicas also suffered some damage.
“Young brassica transplants suffered some damage to their older leaves, but for now, the growing points appear to be alive,” Ballew said. “We’ll know more in a couple days, but we’re optimistic they’ll be able to grow out. Mustard and turnips also have some damaged leaves, but again, the growing points appear to be alive, so we are hopeful here also.”
Strawberries in the Pee Dee
Bruce McLean, Clemson Extension commercial horticulture agent in the Pee Dee Region, said damages to blueberry crops in this region of the state were seen early Sunday morning.
“About all of the Pee Dee experienced temperatures in the mid-to-low 20s,” McLean said. “The lowest temperature I heard about was 22 degrees in the Loris area, but I am sure lower temps were probably observed.”
Freeze events like this are extremely difficult to protect against, he said.
“Often, running overhead freeze protection leads to worse damage than not protecting at all,” McLean said. “In contrast, the localized freeze that occurred Sunday night and Monday morning was much more conducive to having ideal freeze protection. Unfortunately, blueberry growers have experienced these conditions more over the last few years.”
McLean said it may take a few days for growers to realize the extent of cold injury to their crops, adding fungicide applications may need to be made to guard against fungal development.
“Strawberry growers should be on the lookout for increased fungal activity due to the increase in moisture,” McLean said. “Botrytis has really started to show up this past week. Leaf spot is on the rise, too. Be sure to remove any cold-damaged flowers and tissue, and any infected tissue. Also, fungicides targeted for Botrytis are likely needed. Getting a handle on Botrytis early in the season will pay off on maximizing fruit quality and pack-out come harvest season.”
Apples and peaches in the Upstate
Apples in the Upstate are expected to have taken a hit but effects of the weekend freeze will not be known for a while. Kerrie Roach, Clemson Extension commercial horticulture agent for the Upstate Region, said one weather station reported below freezing temperatures for about 20 hours and below 25 degrees for about 12 hours.
“We did have some early varieties like Mutsu in ‘tight cluster’ stage in some orchards, but most of the crops were in ‘half-inch green’ or earlier,” Roach said. “There definitely will be damage from the cold temperatures, but it’s unknown if it will be a thinning of varieties or loss.”
Upstate peaches also may suffer a loss.
“I would be confident in saying that any of our peaches that were in bloom are a loss,” Roach said. “Mid- and late-season varieties should be ok, but again we will not know the extent of damages until a week or so.
“The biggest thing for us is that it’s just March, we still have more than a month to go before we’re in the clear of potential frost and/or freeze events.”