The Valley's Almond Harvest Starts with a Cloud of Dust

A smoke-like cloud of dust billows skyward, rising from deep inside a stand of almond trees.
No, it’s not some unusual mid-summer twister emerging from the orchard. Rather it’s the sign of analmond tree shaker at work.

The first almond tree shaking is taking place in the Westside.

Yes, we can officially drop the green flag on the start of the long almond harvest season in the San Joaquin Valley. Field scout Jenna Mayfield reports sighting the first tree shaking taking place in a Westside almond orchard near the Interstate 5 corridor. This region gets more summer heat and usually is the first region in the Valley to start shaking nuts off the trees.

From now until early fall, growers will be busy harvesting nuts. Starting off the harvest are the soft shell varieties such as nonpareil. The hard shell varieties such as padre and mission are shaken off the trees toward the later part of the season.

“We see shaking into October,” Jenna says. The harvest lasts into the fall for a couple reasons. First, growers plant different almond varieties in each orchard, meaning they will come back a couple times to knock off the nuts. Second, an area’s climate will impact the timing of harvest – usually the areas further east are a bit cooler and almond hull split occurs later than in the hotter locales.

It's important to pick up the almonds as soon as they dry.

Usually, the shaken almonds will dry on the ground for a week or more and then growers will sweep them up for hauling to a processor. Growers try to pick up the nuts as soon as possible to avoid pest damage. Jenna says the heat and humidity trapped under the orchard canopy can prolong the drying process on the ground, leaving the almonds vulnerable pest damage.

 For growers still waiting to start shaking their trees, there are a lot of harvest preparations still ahead. University of California extension advisors advise growers to make a final check for ants on the orchard floor. Tackling ant infestations early can save 140 pounds of nuts, based on an average yield of 2,000 pounds per acre, according to a UC study.

While ant bait is the most effective, it can take several weeks to get rid of a whole colony. If the harvest is about two weeks away, then growers can apply a conventional spray. Jenna reminds growers to continue monitoring for navel orangeworm and peachtwig borer as well.

Growers will irrigate their orchards between shaking.

The last pre-harvest irrigation should be about two weeks before shaking. This will allow the soil to be dry enough for the trees to withstand bark damage due to shaking. Farm advisors point out that the type of soil will determine the time between irrigation and shaking. Sand requires less time for drying while clay needs more time to dry.

Orchards with sandy soils, which hold less water, may require irrigation between harvesting the different varieties. Proper water management between varieties is important because this is the time the trees develop the fruit buds for the next season, UC IPM says.How do growers come up with the start time for harvest? The basic test is striking a tree limb to see how many nuts fall off. Growers should test shake a few trees. The entire orchard is ready once 99 percent of the nuts are shaken from these test trees. Growers also look for any bark damage during the tests. If there are signs of any damage, then they should wait a few days and test again. Bark damage can open the way for diseases.

Mechanical shaking can be tried out when the interior section of the orchard reaches full hull split. The best results for mature trees are when shaking is done at 100 percent hull split.

Meanwhile in the fields, our field scout Carlos Silva says growers are starting to harvest their alfalfa again. The pest on his watch list is the spotted alfalfa aphid, which can be more troublesome that the pea aphid. Counts are up for the spotted alfalfa aphid, but still short of the treatment threshold.

Spotted alfalfa aphid can be trouble.

Carlos also is spotting aphids in the cotton fields, but they aren’t a threat until the bolls start to open up. Lygus isn’t a problem right now, either. He’s finding a good number of beneficial insects such as big-eyed bugs.


The cotton plants are continuing to develop nicely. “The plants are at 12 fruiting nodes. Retention is still good,” Carlos adds.