Low chill hours might have saved peach crop

For the first time that anyone can remember, Middle Georgia’s peach crop is expected to suffer damage from both low chill hours and a late freeze, but it could have been a lot worse.

“It’s unprecedented what we’ve seen this year,” said Jeff Cook, the county agent for Peach and Taylor counties. “We’ve seen low chill. We’ve seen freezes. I don’t know that we’ve seen low chill with a freeze.”

Temperatures dropped into the mid-20s on March 16, which ordinarily would spell disaster for peaches, but the loss is not believed to be significant. Had there been a normal number of chill hours over the winter, he said, most of the trees would have been blooming at the time of the freeze.

As it was, only the earliest varieties were blooming, and most of the trees are not believed to have been harmed.

“If we had 1,000 hours of chill and then warmed up like we were warming, we would have lost everything, probably,” Cook said.

Only one variety, Carored, is believed to be near a total loss from the freeze. Cook said some other early varieties lost up to 40 percent of blooms to the freeze, but since growers thin peaches anyway, that is not as bad as it sounds. Later varieties were not blooming at all and are not believed to have been harmed.

South Carolina had 200 more chill hours, and more trees were blooming at the time of the freeze, Cook said. Estimates there are that about 85 percent of the crop may have been lost. Temperatures there were about the same, so the difference between the two states was the chill hours.

Lee Dickey, vice president of Dickey Farms in Crawford County, said he remains concerned about the impact of the low chill hours, but he agreed it could have helped the crop survive the freeze. The only question now is to see just how much low chill has hurt the crop, which is difficult to tell until the trees start producing.

“I would rather be in my position than in South Carolina’s position because they don’t have a chance,” he said.

Peach trees need a certain number of hours under 45 degrees in the dormant stage in order for trees to produce a full crop. Ideally, Middle Georgia growers like to have 1,000 chill hours, but 850 would cover most varieties.

Chunxian Chen, a researcher at the U.S. Department of Agriculture’s Southeastern Fruit and Tree Nut Research Laboratory in Byron, said their station registered a record low of 520 chill hours this past winter, with the cutoff date being Feb. 15. The laboratory has about 400 acres of peach trees for research, and Chen said only their earliest varieties saw significant loss from the freeze, despite recording a low of 23 degrees in the orchard.

He agreed that the freeze loss might have been much greater had it not been for the low chill hours.

Although a warm February can cause peach trees to bloom early, Cook said that will only happen after trees have had enough chill hours through the winter. Without sufficient chill hours, the blooms will be delayed even if spring comes early.

Cook had already estimated that about 25 percent of the crop could be lost due to low chill hours, but that won’t be known for sure until the later varieties start blooming, which could be a couple more weeks. The later varieties are the ones that require the highest chill hours and could me the most harmed by the warm winter.

“We’ve got peaches,” Cook said. “It’s hard to tell what the crop is.”

This story was originally published March 27, 2017 at 5:14 PM with the headline "Low chill hours might have saved peach crop."