The olive tree, Olea europaea, is one of the oldest cultivated fruit trees in the world. Spanish missionaries first brought the olive to California in the 18th century. Today, California is the dominant olive producer in the United States, supplying nearly all of the nation’s commercially grown table olives and a significant, growing portion of its high-quality olive oil.
Geographic Distribution of Olive Cultivation
California’s olive production is concentrated in two major areas that span the length of the state’s interior. The Central Valley, encompassing both the Sacramento and San Joaquin Valleys, is the powerhouse of commercial olive production. This long, fertile plain provides the bulk of the state’s supply for both canned table olives and high-volume oil.
The highest-volume production is centered in the southern San Joaquin Valley, with Tulare County alone often accounting for over 56% of all California ripe olive acreage. Other counties like Fresno, Kern, and Madera contribute to this vast agricultural output in the south. These areas feature the expansive, flat acreage necessary for mechanized farming and large-scale orchards.
Further north, the Sacramento Valley contributes a large portion of the harvest, particularly in the counties of Glenn, Tehama, and Butte. These counties, along with the northern San Joaquin Valley, are where the bulk of the traditional, lower-density orchards are located for table olive production. This inland geography, with its hot summers, is highly conducive to uniform fruit ripening.
A distinct segment of olive cultivation occurs in the Northern California Foothills and Coastal Valleys, particularly in regions like Sonoma and Napa. This production is typically smaller-scale and artisanal, focused on estate-bottled, extra virgin olive oil. Wineries frequently grow olives alongside their vineyards, capitalizing on the similar Mediterranean climate to produce small-batch, high-value oils that are often hand-harvested.
Varietal Focus and Industry Segments
The type of olive grown in California is directly linked to its intended use, creating two distinct industry segments. The traditional table olive industry relies heavily on two Spanish varieties, Manzanillo and Sevillano, which are primarily grown in the Central Valley.
Manzanillo is the most popular canning olive due to its high flesh-to-pit ratio. Sevillano olives are characterized by their large size, making them particularly suitable for stuffing and gourmet preparations. These table olive orchards are typically planted at lower densities, often requiring significant hand labor for harvesting and pruning, which contrasts with the modern push toward mechanical harvesting.
The growing olive oil segment favors high-yield varieties that can be grown in super-high-density (SHD) systems. Spanish varieties like Arbequina and Arbosana, along with the Greek Koroneiki, are preferred because their growth habit allows for complete mechanization using over-the-row harvesters. This shift to SHD orchards has significantly lowered production costs and increased the state’s olive oil output. Other varieties, such as the Tuscan Frantoio and Leccino, are also widely cultivated for their specific flavor profiles in high-quality oil production.
Environmental Factors Supporting California Growth
California’s suitability for olive cultivation is fundamentally driven by its Mediterranean climate, a pattern characterized by warm, dry summers and cool, wet winters. The olive tree thrives in the intense, prolonged summer heat of the Central Valley, which is necessary for the fruit to properly mature and accumulate oil. This arid period also helps to reduce the incidence of fungal diseases that are common in more humid climates.
A period of winter chilling is also required for the trees to successfully flower and set fruit the following spring. Olive varieties grown in California generally require between 200 and 300 chill hours to ensure a strong bloom. Without this sufficient chilling, fruit production is minimal, which limits commercial olive growing to areas that reliably experience these cool winter temperatures.
Olive trees are notably tolerant of marginal soils, preferring well-drained compositions. While they are drought-resistant once established, the preference for well-draining soil is important to prevent root diseases. The ability of the olive tree to flourish in less fertile ground makes it a sustainable crop choice in California, especially in areas where water resources are becoming increasingly restricted.