If you love creamy avocado slices on your salads, and rich guacamole with your chips, perhaps you're curious about the origins of the mysterious fruit the Aztecs called "ahuacatl." Even though you can find avocados in the produce section of nearly every grocery store in the United States, the strange history of this delicious fruit is far from ordinary.
The cultivated avocado tree probably never existed in the wild and is the result of selective breeding from an unknown wild ancestor. Avocados are thought to have first been cultivated in Central America over 8,000 years ago. Early Spanish explorers noted that avocados were a commonly eaten by the Aztecs and were thought to increase sexual prowess. The Spanish brought avocados to Europe, where they were first cultivated in hot houses by the English.
During the early 1800s, avocados traveled around the globe aboard European ships and were planted throughout the tropics. Avocados reached warm regions of the U.S., like Florida and California, by the mid-1850s. In tropical places, like Hawaii, avocados have naturalized and grow wild from discarded pits.
Today avocados are an important crop, grown across the tropics for fruit, oil, timber, tanning agents and spices. Avocados are a major export in Mexico, Dominican Republic, Brazil and Chile. They are also grown commercially in Australia, Israel, Spain and Indonesia. In the United States, avocados are cultivated in California, Florida, Texas, Hawaii and Puerto Rico. Avocado fruits are an ideal export crop because they can be picked weeks before they are ripe, then shipped and sold while still firm.
Although all edible avocado trees are all the same species, three different types are recognized. The groups, known as "races," are Mexican, Guatemalan and West Indian. Mexican and Guatemalan types came from mid- to high-altitude parts of the countries for which they are named and produce late-season crops. West Indian types came from the lowlands of southern Mexico and Central America, and typically produce crops early in the season. Hybrids between Guatemalan and West Indian types produce midseason crops.
A single avocado tree bears flowers with both male and female parts, which function at different times of the day. Trees are classified as A or B types, depending on the time of day the female parts are reproductively functional. Avocados can be self-pollinated, by wind, or cross-pollinated by insects like bees. Varieties like "Taylor," "Waldin" and "Lula" produce well when planted by themselves. For the best fruit set on other avocado trees, it is advisable to plant both A and B types, which will produce open flowers of the opposite sex simultaneously.
Avocados do not produce true from seeds, so it is best to start with a healthy grafted hybrid from a reputable nursery.
All avocados will do best where temperatures remain above freezing. Mexican and Guatemalan types can take a few degrees of frost, but West Indian types are killed by freezing temperatures.
Avocados require well-drained soils and are susceptible to root rot if soils are waterlogged. Provide good drainage by amending the soil with fine gravel or sand.
Regular irrigation is important to assure establishment of new trees and proper fruit development. New trees should be watered twice a week for the first three years, unless rainfall is sufficient to keep the soil moist. Water older trees regularly during prolonged drought, especially after fruit set.
Avocado trees should be fertilized every two months during their first year with 1/4 to 1 pound of 6-6-6 granular fertilizer carefully worked into the soil surface around the roots. Feed trees 2 years and older three to four times during the growing season with up to 20 pounds of 8-3-9 granular fertilizer worked into the soil around the drip line.