TULE FOG

What is tule fog?

We here in the Central Valley experience a phenomenon called tule (TOOL-ee) fog. It’s an incredibly dense mist that blankets whole areas in near zero visibility conditions which, while making it great for pistachio trees, aren’t all that conducive to getting around. Luckily, the trees aren’t going anywhere.

Those in colder climates are familiar with snow days- well we get “fog days” where schools open once the fog lifts to allow safe passage on the roads.

What does this mean for pistachios? The protective blanket of fog envelopes the trees from ground to branches and provides consistent daytime temperatures effectively helping the trees hibernate with additional “chill” days. Other ways that it helps?

Moisture: While not as significant as rain, the moisture in tule fog can contribute to the overall hydration of the trees and soil, especially during the typically dry winters in the Central Valley. This helps prevent soil-water evaporation, which is essential for nut growth and development in the spring.

Temperature Insulation: Deciduous trees store energy in the fall for bloom in the spring. When there are freezing and hot temperatures during the winter, this depletes their stored energy, which can cause issues in the springtime at bloom. The moisture in the tule fog acts as insulation. On some days when it’s really thick, the daily high/low temperature difference can be as low as 1 degree Fahrenheit!

Pest Management: Pests don’t do as well in years with heavy fog- the high moisture impacts their habitat. This results in healthier trees and and less pest treatments the following year.

These consistent cool temps and other factors are what enable the fruit of the pistachio to grow to its greatest potential. So the nutrient-dense, great tasting pistachios we grow, owe their peak pistachio-ness to this natural part of the ecosystem. Thanks, tule fog!