Late frost hits SE Idaho potato farm again

Published 11:03 am Wednesday, June 25, 2025

Southeast Idaho farmer Tanner Funk digs potatoes June 23 in a field where no frost damage was found. (Courtesy County Line Farms)

PLEASANT VALLEY, Idaho — Potato farmer Tanner Funk feared a weather-related repeat of each of the last two years.

“When I saw frost on my truck windshield, I almost didn’t want to go dig in the fields,” Funk said early June 23. Funk is a partner and director of potato operations at the sizable County Line Farms.

Freezing temperatures hit southeast Idaho over the June 21-22 weekend and into the early morning of Monday, June 23. Temperatures dropped to 30 or 31 degrees depending on location within the farm, Funk said.

Each Monday and Thursday, he and a crop agronomist dig potatoes in selected fields to check moisture, plant health and other indicators of progress compared to a week earlier.

On the June 23 dig, some frost was found on plant leaves — especially in low areas of westerly fields closest to the desert — “but we feel it wasn’t to the extent we had seen last year,” Funk said.

Frost hits harder when it comes in off of a dry area, he said. Some 30-35% of the farm’s westernmost growing area could have sustained some damage, though it takes a day or two following a dig to determine the extent.

A year ago following a dig, “I could smell burned foliage,” Funk said. “Luckily this year, I couldn’t.”

How long temperatures stay at or below freezing is a big factor, he said.

“This year, it didn’t seem to stay as cold for as long,” Funk said. But wind ahead of the frost stressed plants, which “had a pretty rough three days.”

“When it freezes in late June, basically you start all over,” he said.

Digging under the potato plant this time of year typically reveals eight to 12 tubers established per seed piece, Funk said.

“If that plant gets frozen, it will stop feeding those tubers and start new ones,” he said. In the Russet Burbank variety, “you don’t want to see 20 tubers underneath the plant because they will never get to our certain size” per contract standards.

“Quality is big for us,” Funk said. “The only way to break even is to maintain that high standard of quality. Frost will affect quality and yield.”

He typically digs two plants in two fields — one on the north and one on the south, or one each in high or low spots, for example. Goals include determining how much nitrogen should be applied to potato plants and assessing disease and insect pressure.

Following a dig, the seed piece is covered so the plant can keep progressing, “but they don’t bounce back 100%,” Funk said.

The farm grows 11 varieties of potatoes — mainly for fry processing — on about 4,800 acres in 33 fields.

“Overall, things look pretty good,” Funk said. “We are digging potatoes we should be digging July 7 instead of July 23,” indicating the crop is progressing ahead of schedule. “Some varieties are still catching up.”

Last year and in 2023, freezes occurred June 21 and June 20, respectively.

Compared to a year ago, while late-June frost damage to potato plants appears to be lower, input costs are higher and contracts call for decreased acreage and price, Funk said.

“We have to have an above-average crop to get out of the cycle,” he said.

The farm also grows wheat, corn, sugar beets and alfalfa — all down in price from a year ago, Funk said.

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