The Key lime (Citrus aurantiifolia) is a distinct citrus variety valued for its intense aroma and tart flavor. It is noticeably smaller and more spherical than the common grocery store lime, the larger, seedless Persian lime (Citrus × latifolia). The Key lime has a thinner rind and a higher seed count. Although often picked when green, its fully ripe color is pale yellow, and its unique acidity makes it preferred in many traditional recipes.
The Historical Origin of Key Limes
The ancestral home of the Key lime is the tropical regions of Southeast Asia, specifically the Indo-Malaya archipelago, including India and Malaysia. The fruit is believed to be a natural hybrid involving the citron and a wild papeda species native to the area. Arab traders facilitated its initial spread, carrying the plant westward across North Africa and into the Mediterranean region, particularly the Iberian Peninsula, during the medieval period.
From Europe, the fruit’s journey continued to the New World in the 16th century, brought by Spanish and Portuguese explorers. The lime was introduced to Hispaniola, now Haiti and the Dominican Republic, early in the exploration period. This allowed the lime to become naturalized throughout the West Indies, Central America, Mexico, and eventually the Florida Keys, where it earned its common name.
Primary Global Cultivation Areas
Today, the vast majority of commercially produced Key limes originate from tropical and subtropical nations outside the United States. Mexico is a dominant force in the global lime trade, where the Key lime is often called the Mexican or West Indian lime. Producers in Mexico and other Latin American nations like Peru supply a substantial portion of the international market.
Significant cultivation also occurs in parts of Asia and the Middle East. India is the world’s largest overall producer of limes, though much of its crop is for domestic consumption. Egypt and various countries in the West Indies are also notable growers contributing to the global supply. Although the fruit is synonymous with the Florida Keys, large-scale commercial farming there was abandoned after a devastating hurricane wiped out the groves in 1926.
Growers subsequently shifted to the hardier, less disease-prone Persian lime, which is easier to harvest and transport. Although large commercial operations are gone, small-scale cultivation for local markets and home growing still occurs in warm US states like Florida, California, and Texas. Key limes found in most North American markets are imported from major production centers like Mexico.
Essential Environmental Needs
The Key lime tree is extremely sensitive to cold, limiting its growing range to warm, tropical, and near-tropical climates. It requires consistent heat and high humidity to thrive, with temperatures consistently above 60°F being ideal. The tree is highly susceptible to frost; foliage damage occurs near 30°F and death below 29°F, severely restricting its ability to survive temperate winters.
For optimal growth, the trees need full sun exposure, ideally receiving six to eight hours of direct light daily. The preferred soil is well-drained and light-textured, with a pH that is slightly acidic to neutral (6.0 to 7.0). While the trees can tolerate the high-pH, calcareous soils found in the Florida Keys, they require good drainage and will not survive in waterlogged or heavy clay conditions. These strict requirements explain why commercial production is concentrated in a few climatically suitable belts globally.