After a slow start, beginning in Kern County following the Labor Day weekend, the pistachio harvest had kicked into high gear throughout California’s San Joaquin Valley. Because of wide variations in nut maturity this year, many growers are expected to shake their trees a second time. As a result, this year’s already-late harvest is likely to extend into the second or third week of October, veteran pistachio industry member Jim Zion told Tree Nut Farm Press.

A managing partner in Meridian Nut Growers at Clovis, Calif., he’s also the new chairman of the American Pistachio Growers, formerly the Western Pistachio Association.

“It’s a good time to be a pistachio grower,” says Zion. “This is shaping up to be another good year. We’re having very good sizing of pistachios as a result of good pollination, adequate water and good weather. And, the nuts are very clean, with very little staining.”

What’s more, he says, growers in Iran, once the world’s leading pistachio producer, are facing another short crop due to unusually hot weather and inadequate supplies of irrigation water.

“This will be the third year that we’ve out-produced Iran,” Zion says.

Glenn County walnut harvest

This year’s walnut harvest in Glenn County got under way the third week of September, when growers began shaking Ashleys. Next up were Vinas and Serrs, followed by Tulare and Howards.

Growers are expected to wind up the season toward the end of October when they will pick up the last of the Hartleys and Chandlers.

Despite blooming about two to three weeks later than usual, due to cool temperatures in the spring, the mid-season varieties took advantage of some hot summer weather and appear to be making up some of the lost ground.

As a result, nuts reached maturity only about a week behind normal, Bill Krueger, University of California Cooperative Extension farm advisor for the county, told Tree Nut Farm Press.

Growers want to prevent a repeat of last year’s late harvest, when many of them got caught with nuts still on the trees when fall rains began. Consequently, he notes, a number of them have been spraying trees with ethephon to shorten the harvest period.

Applied when walnuts reach maturity, or shortly thereafter, the plant growth regulator accelerates hull cracking and separation from the shell. This advances walnut harvest by four to seven days, depending on the season and variety. Also, it can increase nut value by promoting lighter kernel color and, possibly, by reducing insect damage, Krueger says.

“Last year, quite a few growers in the county used ethephon. I think even more will be using it this year.” He advises growers to check with their hullers before treating with ethephon to insure an orderly harvest and to avoid a backup at the dehydrator.

Read more of what Zorn and Krueger have to say about this year’s walnut and pistacho crops year in the archives of Tree Nut Farm Press at where you can see the most recent issues and subscribe to the free enewsletter that is emailed twice monthly through the growing season.