One science experiment that children try in school is to root an avocado in a glass of water. Avocado seeds root quickly and sprout into a tree. Unfortunately, the tree grows very large and is not suitable as an indoor plant. Many people throw out avocado plants because they cannot produce the proper environment for them to grow in.
The avocado tree is native to central and South America. There the fruit is a staple to the diet of local populations. Avocado is an ingredient in sauces such as guacamole, as well as a garnish on many other dishes. Early Spanish explorers produced the first written accounts of the avocado when they described local foods that settlers on the Isthmus of Panama consumed. During this time, the fruit was known variously as aguacate, aoacatl or palta. Avacado is most likely a corruption of the word aoacatl.
In the United States, avocado trees grow best in tropical and subtropical areas such as southern California, Texas and Florida. The most popular commercially grown avocado hybrid, the Hass avocado, was developed in California. California remains the only state to commercially grow avocados on a large scale. In Texas, avocados are planted in the Rio Grande Valley. Most avocados in Florida are planted in Miami-Dade County. Other major avocado-growing areas include Mexico, Chile, the Dominican Republic and New Zealand. In parts of Texas, avocados are known as a dooryard tree because the trees are planted near homes where the microclimate created by the structure helps to shelter the tree from damage.
Most avocado plants are extremely sensitive to cool weather and will not tolerate frost. Hardier varieties may return from the roots after frost damage has killed them to the ground, while more sensitive cultivars may never return after a period of moderate cold. The tree prefers well-drained soils and will not stand root rot. Typically the tree will grow well if planted on the south side of a hill or on the south or southwestern side of a house where drainage is diverted away. Because avocado trees grow so large, they should never be planted closer than 8 or 10 feet from a home.
Avocados require a tropical climate to thrive. They will be killed or damaged in subtropical climates that receive frost or freezing weather once every 5 to 10 years. The ideal USDA hardiness zones for avocados are typically between zones 9 and 11. Tender avocado varieties will not grow in zone 9, but hardy varieties such as the Hass avocado will tolerate zone 9 temperature ranges.