What’s better for nuts, warmer or cooler? Durham grower explains – Chico Enterprise-Record

Dax Kimmelshue, a Durham walnut and almond grower, inspects an almond tree south of Durham, California, Tuesday, June 20, 2023. Kimmelshue cut one of the maturing almonds open and said the nut has started to solidify – a good sign. (Ed Booth/Enterprise-Record)

DURHAM — Hot, then cool. Warm, then almost chilly. Humans have certainly noticed some wild swings in weather lately. However, what effect do the undulating conditions have on area crops?

Dax Kimmelshue, a Durham walnut and almond grower, said that while nuts in the valley are accustomed to hot, dry conditions — and therefore keep a predictable schedule when weather matches up — cooler weather with a little bit of moisture has its advantages.

Valley temperatures reached only the low 70s Monday, with 73 as the high at the Chico Regional Airport. That’s a far cry from the 90s typical in the area as the summer solstice approaches.

Kimmelshue said the splash of rain — less than a tenth of an inch, at the wettest spots — didn’t hurt.

“It’s good for irrigation because we don’t have to water much on a day like that,” he said.

On the other hand, Kimmelshue said growers want to get the harvest going on schedule in August; cooler weather slows that process a bit. The west side of the Sacramento Valley is ready for harvest slightly earlier than the east side.

“It may be a temperature difference, or possibly the soil type,” Kimmelshue said. “There’s more clay in the soil on this side. Trees want to hold the crop a little longer.”

When it comes to walnuts, cooler conditions benefit the trees, as that type is susceptible to sunburn, just like humans are. The difference is that significant, prolonged heat degrades the quality of the nut meat.

“If it gets too hot, the only thing you can really do is keep them hydrated, even though that isn’t 100 percent effective,” Kimmelshue explained. “The quality of the meats isn’t as good. It doesn’t do it to every nut, but part of a certain orchard. The processor can’t always sift it out.”

Kimmelshue said this is about the time of the growing season when the nuts “start to get hardened off inside,” meaning the nuts begin to form recognizable items instead of the gelatinous blobs they’ve been so far.

Then, a process called “hull split” takes place, as the exteriors begin to crack. “It shows the nut is maturing, and it starts to dry,” Kimmelshue said.

Nonpareils — the type of almond most consumers prefer, Kimmelshue said — are the first ones to split, with the pollinator variety after that.

Walnuts and almonds also benefit from the cooler conditions because it hampers the ability of mites to attack the trees, Kimmelshue said.

“The mites like it hot, dry and dusty,” he said, “so the tree is healthier when it’s cooler.” It also means the grower doesn’t need to spray as much — thus saving money.

Kimmelshue described prices as being “in the tank” — for almonds, about $1.50 per pound based on meat weight. He said that barely covers the grower’s costs, if it does at all. Also, the industry is still smarting from the effects of COVID, when shipping became a real problem with a work slowdown due to fewer workers, though things have improved lately. Plus, there was an oversupply.

“Getting them down to Oakland, and sometimes Long Beach, for shipment was a challenge,” Kimmelshue said, referring to the shipping ports that would take the nuts to overseas markets.

To offset those tough economics, some growers, like Kimmelshue, are planting “dry, edible beans” in the areas between the rows of trees when the orchards are young and the sunlight can reach the ground.