“About this time it is useful to crack open some nuts and see the stage of development,” said UC Davis professor Tom Gradziel, addressing a crowd of almond growers this May. “This year, the endosperm seems to be taking off late, and the embryo’s right behind it.”

Gradziel said that late development isn’t necessarily bad: a couple years ago under similar circumstances there weren’t any major problems at harvest.

He recommends that growers cut open nuts throughout the growing season, and inspect and eat the nuts to get a feel for the crop’s progress.

“Make a habit of walking through your orchard, cracking nuts open, eating the kernels,” Gradziel said. “It is a way to track the orchard and nut development.”

Almond trees drop nuts in three different stages, he said. Nut drop is nothing to fear, given that trees naturally have far more flowers than nuts.

“You’ve got 60,000 flowers, 100,000 on good-sized nonpareils,” he told the crowd. “Some of those just aren’t competitive.”

The first drop is blooms that are defective. The second, non-fertilized floral cups that are still attached.

Finally, the tree drops nuts that aren’t competitive with better-developing nuts nearby.

This year’s weather is a factor on almost all almond growers’ minds.

“If you have a cold front come in, it affects the ovule, it also affects the pollen,” Gradziel said.

He said almond orchards can take more time to fertilize after pollination than a flower in the lab, up to two weeks for fertilization to be complete.

“If you want a fruit, you need a flower. If you want a flower, you need a vegetative varistem,” Gradziel said.

His point: Growers should keep vegetative growth strong each year for the sake of the next year’s crop.

“If I want to ensure I have lots of flowers next year, I need to ensure I have lots of vegetative growth this year,” Gradziel said.

While some people say nuts grow on second-year wood, Gradziel said, it’s important to have new vegetation to grow a crop.

Another consideration for growers for proper nut development: pruning to keep the canopy open enough for sunshine to come in.

Gradziel said bud failure is self-pruning in a sense, in which the tree lets buds fail to bring more sunlight in.


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