Climate Change Is Forcing Georgia Peach Farmers to Explore New Varieties

While the idea of warmer, shorter winters might sound appealing to farmers eager to tap into longer growing seasons, those engaged in Georgia’s massive peach industry are finding the trend alarming. 

Since 1960, the average winter temperature in Georgia has risen by five degrees Fahrenheit and is predicted to climb even higher by mid-century. For farmers who depend on cold weather to help crops like peaches and blueberries thrive, the state's diminishing winters are a warning to adapt or else.

"One of the interesting things happening is we're starting to see new crops come into Georgia," Pam Knox, an agricultural climatologist at the University of Georgia, told National Geographic. "I'm working with folks now looking at citrus, especially the cold-hardy varieties like satsumas. We're also growing olives in Georgia, which we couldn't do before."

Survival of the Chillest

One of the keys to growing the perfect Georgia peach is something called "chill hours." Nut and fruit trees (with the exception of citrus) require a certain number of chill (aka dormancy) hours below 45°F to regulate their growth. Without the requisite amount, flower buds may be delayed or erratic in spring and fruit set and fruit quality will be poor. In Georgia, home to nearly 12,000 acres of peach orchards, the average peach tree requires anywhere from 650-850 chill hours each season. 

"The problem is that, year after year, the weather is very variable. And we’re getting warmer winters, which is creating some fluctuation in the chill accumulation and that quality of chill that they acquire," Dario Chavez, an associate horticulture professor at the University of Georgia (UGA), told Modern Farmer. 

The impact from a loss of chill hours was felt most recently in 2017, when farms across the state averaged less than 400 hours and 85% of the peach crop was lost. "It was so bad we thought they were not going to come out of dormancy," Chavez added to NatGeo. "We didn't care about the blooms anymore; we wondered if the plants would survive."

As temperatures climb over the next several decades, average annual chill hours for different agriculture zones in Georgia are expected to shift in response. "Chill accumulation is reducing," Chavez told The Counter. "If you look at the historical data, you will see a downward trend... Sooner or later, you will not be able to grow [peaches of] certain chill groups that you used to be able to grow."

Finding 'Joy' in New Varieties

While planting new varieties of peaches that require fewer chill hours is part of the solution, it's not the only characteristic that's necessary. Despite warmer, shorter winters, Georgia still experiences a consistent frost in early March. Peach varieties with fewer chill hours often bloom earlier, making them particularly susceptible to these bouts of freezing spring temperatures.

In response the USDA is experimenting with hybrid varieties that achieve the delicate balance of low chill and normal bloom. These include three recently released varieties of yellow peaches: Liberty Joy (650 chill hours), Crimson Joy (700 chill hours), and Rich Joy (800 hours). The days of planting 1,000+ chill hour varieties in Georgia may be gone, but the hope is that continued research into global warming-tolerant varieties may keep the state's official fruit firmly in the sweet spot of American produce.

"We’ve got to keep changing as the environment, as everything else changes," Georgia farmer Lawton Pearson told WABE. "But it's not something that scares us in the slightest about the future of growing peaches. It's just something you’ve got to deal with. We don’t have a choice."