The kiwi fruit (Actinidia deliciosa) is often associated with international imports, particularly from New Zealand. However, a significant portion of the kiwi consumed in the United States is cultivated domestically. This prickly, oval fruit with its bright green flesh is grown in specific American regions that meet the unique climate requirements of the vine.
Essential Environmental Requirements for Kiwi Vines
Commercial fuzzy kiwi vines require specific environmental conditions, particularly during winter dormancy. The plants need chilling hours, which is the accumulation of time spent below 45°F (7°C). The ‘Hayward’ variety typically requires between 600 and 700 hours of this winter cold to break dormancy and stimulate uniform bud break in the spring.
The growing season must be long and reliably frost-free, generally requiring 225 to 240 days for the fruit to mature before harvest. Kiwi vines are highly vulnerable to damage from late spring frosts, which can destroy new shoots and eliminate the season’s crop. Suitable soil is also necessary, preferably a deep, well-drained sandy loam with a slightly acidic pH, as the vines are sensitive to waterlogging.
The Major Commercial Hub: California
California is the dominant commercial producer of fuzzy kiwifruit in the United States, accounting for nearly 95% of the nation’s output. The Central Valley provides the ideal Mediterranean climate, featuring mild winters that supply the necessary chilling hours. This is combined with long, hot, dry summers that ensure a prolonged, frost-free growing season for fruit maturity.
Commercial production is concentrated in the San Joaquin and Sacramento Valleys, particularly in counties such as Tulare, Butte, and Fresno. These areas provide the reliable winter chill needed to set fruit. The primary variety grown is the ‘Hayward’ kiwi, which is the large, fuzzy-skinned fruit most commonly found in grocery stores.
The industry depends on irrigation to sustain the vines through the summer months. Growers train the vigorous vines on T-bar trellises to manage their sprawling growth and maximize sun exposure for the fruit.
Cultivation in Other States
Beyond California’s large-scale operations, kiwi cultivation occurs in other regions utilizing different, more cold-tolerant species. The Pacific Northwest, including Oregon and Washington, is a secondary area focusing on the hardy kiwifruit. These vines are cold-hardy, capable of surviving winter temperatures as low as -10°F to -25°F, making them suitable for much colder climates than the fuzzy kiwi.
Hardy kiwis, often marketed as kiwiberries, are smaller, about the size of a grape, and possess a smooth, edible skin that eliminates the need for peeling. This variety has a shorter chilling requirement, making it adaptable to a broader range of US growing conditions, including the Eastern seaboard and Midwest. Oregon is a leading producer of these kiwiberries, though they have a shorter shelf life compared to the commercial fuzzy kiwi.
Cultivation also occurs in the Southeast, though these efforts face challenges from high humidity and inconsistent winter chilling. Growing kiwis outside of California relies on selecting hardy, small-fruited varieties that can withstand lower temperatures.