California is the dominant force behind the domestic fresh plum supply, producing over 95% of the plums grown in the United States. California’s Mediterranean climate and vast agricultural lands create ideal conditions for growing stone fruits, including plums. The availability of fresh plums begins in the late spring and extends well into the fall, providing a sustained market presence for several months.
The Overall California Plum Calendar
The fresh plum season in California generally starts in mid-May and can last until late September or early October. The earliest harvests often begin with Japanese plum varieties, which ripen quickly under the spring sun. This initial push marks the start of the season, but the volume is relatively light.
The peak availability for plums occurs during the summer months, specifically throughout July and August. During this period, the greatest number of varieties are simultaneously reaching maturity, leading to the highest volume of fruit in grocery stores and farmers’ markets. As the summer heat wanes, the season tapers off, concluding with the last late-maturing plums harvested before the cooler weather arrives in autumn.
Key Varieties and Their Harvest Windows
The length of the California plum season is sustained by the sequential ripening of two main plum types: Japanese and European. Japanese plums are typically rounder, juicier, and less sweet than their counterparts, and are the first to be harvested, starting in May. Varieties like the popular Santa Rosa plum fall into this category and are frequently enjoyed as fresh eating fruit.
European plums, often used for drying into prunes due to their higher sugar content and firmer texture, ripen later in the summer and into the fall. These varieties, such as the Italian or French prune plums, help extend the season toward its October end.
Adding to the diversity of the harvest window are interspecific hybrids, such as Pluots, which are a cross between a plum and an apricot. These fruits, known for their smooth skin and intense sweetness, have their own specific harvest times that fall within the general plum season, often peaking in the mid-to-late summer. Cultivars like the Dapple Dandy Pluot are available during the season’s peak.
Regional Influence and Seasonal Variability
The vast majority of California’s fresh plums are grown in the Central Valley, specifically within the San Joaquin Valley south of Fresno. This region provides the high summer heat and necessary irrigation for optimal plum development. The concentrated nature of the farming area means that regional weather patterns heavily influence the harvest schedule across the state.
The stated harvest dates represent historical averages, but the actual timing can shift from year to year due to weather variability. For instance, a late spring with unexpected rains or a period of unusually cool weather can delay the start of the harvest by one to two weeks. Conversely, an early summer heat wave can accelerate the maturation process, pushing the peak harvest forward.