Borrego Sun - Since 1949

Pistachio lovers might have to search further down their pockets to pay for the nut because this year appears to one of the worst pistachio harvests ever in California. In the Central Valley, where 98 percent of the state's pistachios are grown, shells have turned up empty. The female trees are delivering 70 percent of their harvest in empty shells which is due to warmer winters.

Pistachio trees, male and female, use the cold temperatures during winter to know when to bloom in spring, at the same time. When there is a warm winter, the male blooms later, leaving its female counterpart unfertilized, but still producing empty shells. Pistachio harvest begins in early September.

Also affecting the pistachio harvest is the state Drought. Winter fog protects the trees from direct sunlight, though California, in its fourth dry year, has not produced enough fog to protect the trees.

Some farmers resort to alternative sources for a better harvest, like spraying oil on the trees to help them bloom more uniformly, though that doesn't always work, and spraying the trees at the wrong time and temperatures, can cause damage. There are other breeds of pistachio trees, but they require several years before they can be harvested. This year's harvest is predicted as an all-time low, however, experts say it's too early to know how the harvest will be.