Orchardist experts from Florida, Georgia, and South Carolina share their perspective on the current accumulation of winter chill and how it might affect the upcoming harvest season.

Winter Chill Offers Promise for 2018 Crop

by CHERYL ROGERS

After what was a devastating season for many in 2017, some peach growers in the
southeastern United States were cautious yet optimistic as winter freezes brought in
needed chill hours for the 2018 crop.

“The trees look the best to me in three years,” says Benny McLean Jr. of McLean
Family Farms in Clermont, Florida, formerly known as Uncle Matt’s Organic. He
reports as of January 18 that his trees were pretty much dormant, with red wood and a
“thimble full” of blooms. “There are more spiders in the tree than there are flowers,”
says McLean, who sells direct to the public through u-pick.
For now, they must wait. “We have to get through February and March,”
explains McLean, who didn’t have chill hour statistics for his area. “We hold our breath
for the next 75 days.”

In Middle Georgia near Macon, Lee Dickey, co-owner of Dickey Farms, also
was cautious. “It’s too early to say. The good news is that we are certainly ahead of
where we were last year,” he says. The area logged about 800 chill hours by January 19,
close to the historical average, according to Dickey. “A year like last year is vey rare.
Hopefully, it will continue to be a rare occurrence,” he adds.
An unseasonably warm winter, followed by a freeze, was bad news for many
southeastern U.S. peach growers in 2017. But some in Florida benefitted from a longer
season when supplies dwindled farther north.

Peach experts in Florida, Georgia, and South Carolina all are hopeful for a good
year this year because of the winter chill. “We are doing a lot better than we were doing
last year,” says Dario Chavez, assistant professor in peach and extension for the
University of Georgia in Griffin, who is the state’s peach specialist.
The area had logged 841 hours by January 22, compared to 373 hours by January
21, 2017. “We’re okay if we keep accumulating chill,” he says. “All of us are pretty
excited for this season,” he adds. “Some still probably need a good season to recover
[from last year].”

If any sustain damage this winter, it won’t be evident until the trees come out of
dormancy— and goo oozes from blisters on trunks and limbs.
Jeff Cook, an area peach agent and County Agriculture Agent in Taylor and Peach
counties, GA, estimates middle Georgia had about 750 hours or more by January 18.
“We should have adequate chill for most of the varieties grown in our state,” he says.
Ideally, the area will obtain 1100 to 1200 chill hours. “We need 850. We would love
950 and above,” he says.

South Carolina growers are also faring well thus far. “We’re in the green on
chill hours,” says Greg Henderson, area commercial fruit agent for Clemson University
Extension Service. “We’ve had pretty uniform temperatures, both normal highs and
lows— other than those couple of weeks of arctic weather.”
The area logged about 860 hours by January 23 compared to 476 in a similar time
frame last year, which means South Carolina growers are focusing on more routine
concerns: like when will the blooms come and whether they’ll be a prolonged warm
spell.

Florida growers heading for commercial markets are straddling a fine line. “It
[the cold] is a double-edged sword. Having chilling is very good,” says Chris Oswalt, a
University of Florida/Institute of Food and Agricultural Sciences extension agent in Polk
and Hillsborough counties. “In getting their chilling requirement, they also need to have
these trees start producing, setting fruit at a specific period of time.”
Florida’s peach industry, which relies upon varieties bred for the Sunshine State’s
warmer climate, aims to reach market by April— before the Georgia crop. Since it takes
about 85 or 90 days for fruit to develop, a February 1 bloom date is a bit late. “If the
climate is such that it pushes out past where you need to be flowering and setting fruit,
you may miss your market window,” Oswalt explains.
Steve Callaham, managing partner of Dundee Stone Fruit Growers Association,
which represents some 700 acres in Florida, says growers are “looking forward to a good
crop. Most orchards are blooming now,” he reports in a Jan. 23 interview. “It looks
really good. We hope, with the chill we’ve accumulated this year, we’ll be able to meet
that demand.”

Meanwhile Ali Sarkhosh, Ph.D., an assistant professor of Tree Fruit and
Viticulture at the UF in Gainsville, also was optimistic. “In general, I think this year will
be much much better than 2017 and 2016 for peach growers in Florida.” He says UF,
which bred lower chill peaches for Florida, will be concentrating on how to produce
peaches by the end of March and with less chill. “We want to have a shorter period of
flowering and then harvest the fruit as soon as we can,” he says.
He’s also looking into how to reduce production costs for the Florida industry,
which has grown from some 400 acres in 2009 to more than 2,000 as the state’s citrus
growers looked for alternatives in light of citrus greening disease. The state produces a
tasty, albeit smaller peach about two inches in diameter. While it’s desirable for
children’s snacks, some prefer larger fruit.

In response to concern that Florida peaches are too small, university students will
be experimenting with a peach cider that may be available by the end of July. “We are
not worried about sizes for peach cider,” Sarkhosh observes. “It has to be something for
maybe selling in the agritourist industry.”

Though the peach industry has traditionally calculated chill based on chill hours
below 45 degrees Fahrenheit, some are experimenting with other ways to calculate chill
that may work better. Through the Florida Automated Weather Network (FAWN),
Florida growers can calculate chill through the Dynamic Model, which relies on chill
portions. “We display the previous five years of chill portions for a selected date range,”
explains Rick Lusher, FAWN director.

In Georgia, Chavez is trying to get all basic models added to the UGA network of
weather stations at weather.uga.edu, that includes:

 Utah, a stricter model that negates chill when temperatures rise;
 Dynamic, which measures chill units, negating some time when warmer
weather occurs;
 Weinburger, the traditional model logging hours under 45 degrees
Fahrenheit; and
 Modified Weinburger, which logs hours between 32 and 45 degrees
Fahrenheit.

South Carolina growers may rely on UGA. Weinburger and Modified
Weinburger model calculations are available at agroclimate.org.