Hard freeze

A hard freeze Oct. 10-11 in parts of Idaho and Oregon damaged some of the onion crop.

Idaho potato growers have been bouncing back from an early freeze that in some locations delayed harvest and raised quality concerns.

“They are taking advantage of the beautiful weather we have right now and getting the rest of the potatoes out of the ground before the next storm hits,” state Potato Commission Industry Relations Director Travis Blacker said. Precipitation and cold were expected in many locations over the Oct. 19-20 weekend.

Growers of several crops, from apples to onions and from sugar beets to wine grapes, felt the effects of unusually low temperatures Oct. 10-11 in parts of Idaho and Oregon.

Blacker said an estimated 15 to 20% of Idaho’s potato crop was still in the ground when the frost hit.

“There is definitely some frost damage out there,” he said. “They are trying to sort that out.”

More will be known after potatoes are sorted, and monitored in storage. Potatoes subjected to hard freezes often don’t store as well as those harvested under normal conditions.

Damage could be an estimated 5 to 30% of potatoes depending on soil type and location, Blacker said. Some areas saw low temperatures of 22 to 24 degrees, some 9 or 10.

“Our lowest temperature was 24,” said Randy Hardy, who grows potatoes 20 miles south of Burley and is a state potato commissioner. “We were pretty fortunate. Much of Cassia County avoided the damaging freeze.”

At his farm, potatoes historically have avoided damage when air temperatures stay above 20 degrees and freezes don’t happen on consecutive days, he said.

Vine canopies froze at Williamson Orchards and Vineyards west of Caldwell, mostly ending grape ripening, co-owner Michael Williamson said Oct. 17.

“We are kind of scrambling to get everything harvested before the stems on the grapes collapse and fruit falls onto the ground,” he said.

The vineyard’s grapes during the freeze were 90-95% ripe. Harvest was just over halfway completed.

“We could have used another week or two of ripening to accumulate more sugar,” Williamson said.

Some onions in southeastern Oregon and southwestern Idaho sustained damage, but “it is still a little early to say how all of that is going to shake out,” said Oregon State University Malheur Experiment Station Director Stuart Reitz.

Damage rates can vary based on the fields and microclimates in which they are grown.

More onions than usual were still in the field when the cold snap hit, after rains delayed both planting and harvest, he said.

Freezes can initiate cell breakdown in outer layers, Reitz said. The onion consequently can be watery and partly discolored depending on how deep the freeze penetrated.

“Instead of the crisp onion you are expecting, those outer layers can be just soft and spongy, and not appealing,” he said. “The more damage there is, the more likely the onion is not going to be marketable.”

In storage, the onion may not hold up as well, and could be susceptible to other rot and breakdown.

Amalgamated Sugar beet growers in western Idaho came out of the freeze relatively unscathed.

“With the temperatures we had in Western Idaho, we didn’t have significant frost damage in the beet itself,” said Greg Dean, the company’s district agricultural manager.

Freezing temperatures damage the leaves atop the beet, reducing the plant’s ability to retain heat stored in the ground. If frost damage is severe enough, the beets will try to re-grow foliage “tops.”

“We did not have any issues along those lines in western Idaho as long as growers did not ‘top ahead,’” Dean said. “They had no long-lasting implications.” Amalgamated asks its growers to leave the tops intact until immediately before beets are harvested so the foliage can provide protection.

Amalgamated was finished with 12.5% of harvest Oct. 10 and 13.9% completed early Oct. 11, near its five-year average, he said.

Idaho Apple Commission Chairman Daniel Rowley, of Cherry Hill Farms west of Caldwell, said temperatures dropped to 19 degrees, “which pretty much froze the apples on the trees. We couldn’t pick for a few days.”

The freeze brought a bit more watercore, which turns the apple watery and increases sugar content in some varieties, such as Fuji, and can produce an “off” taste, he said. Ultimately the freeze “probably will lessen quality in storage a little bit with Fujis.”

Cherry Hill during the freeze had some Granny Smith apples left to harvest, Rowley said, and had not started picking Fujis; that variety sustained “a little bit of watercore, which is OK — as long as we don’t get any more, we will be all right.”

Recommended for you