The most important element to keep in mind when growing a cashew tree is that they originated in the tropical region of Brazil, and, therefore, require warm year-round temperatures to thrive, as they are very frost sensitive. The daytime temperature where these trees are cultivated should not drop below 50° Fahrenheit (10° Celsius) and should average around 80° Fahrenheit (27° Celsius). Cashews can tolerate hot temperatures well, whether wet or dry, and a temperature near or above 105° Fahrenheit (41° Celsius) will not harm them.
Planting a young cashew tree or sprouting the tree from seeds is the least expensive way to get started, but it has its drawbacks. Fresh cashew seeds sprout easily and can germinate within as little as four to five days in well-watered soil. Cashew seeds from any select tree will not grow true to type, however, and will vary from their parent tree to such a level that they may produce little fruit, or the fruit may be nearly inedible. Each fruit on the tree produces a single nut or seed, and can be stored for up to two years in its shell with a strong likelihood that it will still germinate when planted.
A cashew tree can take anywhere from three to five years before it starts to fruit. For this reason, and to develop unique characteristics in cashew nut production, the tree is often grown from a grafting which can fruit in as little as 18 months. When planting a cashew tree outdoors if it was started in a pot, it is necessary to give it a minimum distance of about 33 feet (10 meters) from any other cashew or large plant. They grow to a height of about 40 feet (12 meters) when fully mature.
Caring for a cashew tree once a seedling is established is fairly simple, as they are drought-resistant and can tolerate marginally fertile soils well in which other fruit trees and nut trees would not survive. They prefer well-drained, sandy soil, and, during fruiting and dry periods, should be watered and fertilized with a fertilizer composed mostly of nitrogen, phosphorus, and trace amounts of zinc. Poorly drained soils will inhibit tree growth, and rain during the period when they are flowering can cause the flowers to drop off before pollination due to mildew.
The region for optimal growing conditions for the cashew tree is up to 25° north or south of the Equator. This puts them within range of most of South America, Africa, and Australia. Much of the Far East and Middle East would also have suitable climates, as does all of Central America and Mexico. The trees would also suit the far southern Texas region and all of Florida and Hawaii in the US. Anywhere farther north such as the bulk of Europe, the US, and China, would require protected growing conditions in order for a cashew to thrive.