If you are lucky enough to live in a part of Texas where cashews (Anacardium occidentale) will thrive, you may be able to grow this nut for yourself. Though harvesting and eating the cashews is a fun project for kids, watch out for the potentially poisonous parts of the plant.
Most of us would not recognize the cashew if we saw it growing on a tree. Not only is it attached to a giant cashew “apple,” with red skin and juicy flesh, it is surrounded by a thick, oily shell. Some botanists do not even classify it as a nut, calling it instead a drupe, drupaceous nut or nutty drupe. Although the apple is edible, be careful of the cashew shell, which contains the same toxin compound as poison oak, urushiol, which can cause rash and itching in some people. Leaves are evergreen. The tree grows to a maximum height of around 36 feet.
Cashews are native to tropical parts of the Americas, ranging from Peru and Brazil up through Mexico and into the West Indies. It will grow in tropical regions all across the globe, tolerating both wet and dry climates. It is hardy in U.S. Department of Agriculture plant hardiness zones 10 through 11, and sensitive to cold temperatures. It will sustain damage at 30 to 32 degrees Fahrenheit, so do not plant outside if you have a history of freezes in your area. Unfortunately, only a very, very small area of Texas, near Brownsville, falls into USDA zone 10, so likely cashew will not work in your area.
If you do live in USDA zone 10, you may have some luck growing cashews out of doors. Despite its tolerance of coastal areas, cashew does not put up with saline soil, so wherever you plant it, either use backyard soil with a low salt content or import soil to your yard. Cashews prefer temperatures between 63 and 100 degrees F and a relative humidity of 65 to 80 percent. Water regularly, about an inch every week, and keep water away from fruit or flowers as well as leaves.
Because cashew is often grown in pots at nurseries, there is a chance you may be able to sustain a healthy tree in a pot. Soak cashew seeds for 24 hours, then plant 2 inches deep. You may sow cashews either in peat pots or in the ground during the hottest part of the year. Wait until seedlings are 12 inches tall, then transplant to 3-gallon containers, or plant the entire peat pot if you’ve sown in containers. They will live happily in pots up to 3 or 4 feet tall, and perhaps longer. The most important thing is to transfer the tree before it becomes rootbound.