Georgia Vidalia onions and peaches need wintry temperatures to produce their best in spring and summer. So far, conditions have been excellent, say University of Georgia experts.

“Right now, the Vidalia onion crop is progressing very nicely. We expect acreage to be pretty stable,” said Reid Torrance, the UGA Cooperative Extension coordinator in Tattnall County, where 60 percent of the crop is grown.

Approximately 80 percent of the expected 12,000 acres has been planted. Recent rain has made planting more difficult. “We are having to hop around to find fields dry enough for planting,” he said.

He expects farmers to grow 600 acres of organic Vidalia onions, a 50 percent increase over last year.

“Onions are very tolerant to cold when they are young,” Torrance said. “But, we don’t want a real cold winter. Temperatures in the low teens and single digits bring a risk of cold injury. By the same token, a warm fall and early winter can cause onions to grow too much too soon.”

Several winters in the 1980s wiped out the crop. But more cold-tolerant varieties now help prevent that, he said. The last devastating freeze happened in 1996. Improved varieties and management has helped farmers control diseases in recent years, too.

Onion farmers seed planting beds in September and transplant the young plants from the beds to fields in November and December. They harvest onions in April and May. To be an official Vidalia onion, the onion must grow in one of only 20 counties in southeast Georgia designated by the Vidalia Onion Act of 1986.

While onions use the cool winter months to mature underground, Georgia peach trees need chill hours, or hours below 45 degrees Fahrenheit, to stay dormant. This helps them bloom properly in the spring and produce fruit in the summer.

“Depending on the variety, Georgia peaches like to get between 400 and 1,100 chill hours between October and Feb. 15,” said Frank Funderburk, UGA Extension coordinator in Peach County.

Georgia has 12,000 to 14,000 acres of peaches scattered throughout the state. But most grow in central Georgia. As of Dec. 8, Peach County had received 375 chill hours. “We are ahead of the last three years. We are looking good,” he said.

In recent years it hasn’t been a lack of chill hours, but rather a late freeze that hurt the crop. Freezes in 2007 and 2008 cut the crop by half, he said.

“We can make a crop with low chill hours, but we won’t make a crop if temperatures drop too low after buds start to develop,” Funderburk said.

A freeze in 1996 destroyed the entire crop.

“We are hoping for a better year in 2009. By mid-January we will have a good idea of where we are,” he said.