The cashew tree, Anacardium occidentale, is a tropical evergreen native to the coastal regions of northeastern Brazil. The kidney-shaped nut is attached to the bottom of a swollen, pear-shaped structure known as the cashew apple (an accessory fruit). This plant is exclusively adapted to grow within the narrow band of the tropics, requiring specific climatic conditions.
The Ideal Climate
Commercial cashew production requires high, consistent temperatures and a precise seasonal rainfall pattern. The most suitable average annual temperature range is between 24 and 28 degrees Celsius, though the tree thrives in daytime temperatures up to 38 degrees Celsius. The absolute intolerance to cold is a defining factor, as any exposure to frost or prolonged temperatures below 18 degrees Celsius can severely damage young trees and halt production in mature ones.
Annual rainfall of 800 to 1,500 millimeters is preferred, but the timing of precipitation is more important than the total volume. Cashew trees require a pronounced dry season lasting at least four to seven months for the initiation of flowering and fruit setting. If heavy rainfall coincides with flowering, it can cause flower and fruit drop, leading to fungal diseases and reduced nut yields. The subsequent wet season is needed for vigorous vegetative growth, allowing the tree to accumulate resources for the next reproductive cycle.
Soil and Terrain Needs
Soil must prioritize drainage, as the cashew tree is extremely sensitive to waterlogging and standing water around its roots. Deep, well-drained soils are preferred because they allow the extensive root system to penetrate easily, providing stability and access to deep moisture reserves during the dry season. Sandy loams, coastal sands, and lateritic soils are common in successful cashew orchards, offering the necessary porosity and minimal water retention.
The cashew tree tolerates relatively poor soils and grows effectively in soils with a slightly acidic pH, ideally ranging from 5.5 to 7.0. Commercial cultivation is concentrated at low altitudes, typically up to 600 meters above sea level, where high temperatures are consistent. While cashews can be found at elevations up to 1,000 meters, yields are lower and trees grow more slowly due to cooler conditions.
Global Cashew Production Hubs
The global concentration of commercial cashew production is directly determined by the regions that naturally provide the required dual climate system of high heat and seasonal dryness. The dominance of nations like Vietnam, India, Ivory Coast, and Brazil stems from their combination of consistent tropical warmth and the alternating wet and dry seasons.
In West Africa, the Ivory Coast is a leading producer, utilizing the tropical climate that features the necessary long dry spell for flowering. India and Vietnam benefit from monsoon-driven seasonal rainfall patterns, which align with the tree’s need for a resource-building wet season followed by a reproductive dry period. Brazil, the cashew’s native home, maintains a strong presence in production due to the suitability of its tropical northeastern regions.
Growing Cashews Outside the Tropics
Cultivating cashew trees outside of the true tropical zone presents challenges for commercial nut production, even in warm subtropical or Mediterranean climates. The main obstacle is the tree’s low tolerance for cold weather. While a hobbyist might keep a cashew tree alive in a protected environment, achieving a viable nut harvest is difficult.
The lack of a consistently long, intense dry season in subtropical regions means the tree may not receive the environmental stress required to induce mass flowering. Untimely or excessive rainfall during the potential flowering period can cause blooms to fail, leading to minimal nut yield. The tree requires the precise environmental cues that only its natural tropical habitat can reliably provide.