Cashew Trees are extremely easy to grow, but that is where the straightforward nature of this unique tree ends. The Cashew, more than any other widely consumed nut, is far more than it appears. Most nuts are simply tree seeds, but Cashew Nuts are the seed and the fruit. The Cashew Apple, which appears above each Cashew Nut, is actually the swollen stem end of the branch where each nut grows. The bright red, juicy Cashew Apples are sweet and edible. With care you can also harvest your own Cashew Nuts from the Cashew Tree.
Cashew Trees can be grown in the ground in USDA Zones 9 to 11. You can also grow a Cashew Tree in a container if you are limited on space, or live in Zones 4 to 11. Mature Cashew Trees will reach a height of 12 feet, and a width of about 15 feet. They are self-fertile, prefer full to partial sun, and are fast growing.
Please Note: Cashews themselves aren’t toxic, but they are surrounded by a shell that consists of the toxic oil urushiol. Coming into contact with urushiol can cause itching, blisters, and skin rashes. Please handle with care.
Cashew Tree Care
If you are within USDA Plant Hardiness Zones 9 to 11 and have space for a small tree, plant your Cashew Tree in the ground. Choose a sunny location with soil that drains well. Cashew Trees do well in sandy soils, but can tolerate a richer soil as long as the ground does not retain water and remain soggy. Plant in a hole that is the same depth and twice the width of the tree’s root ball.
If planting in a pot, choose a container with adequate drainage holes. Place your potted Cashew Tree in the sunniest location possible, such as a patio, or south-facing window. Cashew Trees bloom many tiny white to maroon-tinted flowers in the spring and create an ornamental focal point with their dark green leaves, tiny blooms, and red fruit.
Fruit & Harvesting
Cashew Apples can be eaten when they turn red from November through January. They are juicy, sweet, and contain Vitamin C, Vitamin B, and Calcium. The nuts should be handled with care. Cashew Tree Nuts are ready to pick once the Cashew Apples are red. The nuts from under the swollen stem fruit, and the shells contain a caustic substance that surrounds the nut. There are a few methods for safely removing the Cashew Nut from the shell and avoiding the severely irritating liquid inside.
The nuts can be picked using gloves, frozen, and then removed from the shell (again with gloves) before the liquid inside the shell thaws. Use caution and do not get the liquid on your skin, or in your eyes. Another method is to roast the shelled nuts over a fire in a pan with holes, or in heated oil. All methods require caution and careful preparation to avoid coming in contact with the irritating substance protecting the nut inside the shell.
Always prune any dead or dying branches from your Cashew Tree. The best time to prune is after fruit has been harvested in late winter. Cashew Trees respond well to mulching, which retains soil moisture, discourages weeds, and can provide slow-release nutrients. Water a new tree once every two weeks, or when soil is dry down to two inches below the surface.
You can fertilize your Cashew Tree once every three months in the spring and summer after it has been growing for at least two weeks. However, established and mature Cashew Trees require very little added fertilizer, and will fruit and grow nuts easily from the nutrition the tree gathers from decaying mulch, leaves, or compost. Since they are self-fertile, a single tree will grow fruit and nuts, but multiple Cashew Trees will produce more heavily.
Is it true that Cashew Nuts are poisonous before they are roasted?
Not exactly. While this has become a simplified way to describe one aspect of the Cashew Tree, it is actually a protective, caustic liquid that the tree produces between the nut and the shell that has given the nut the reputation of being poisonous.
Can you eat the Cashew Nuts from your own Cashew tree?
Yes. With proper handling and care, the Cashew Nuts your tree grows can be processed and safely eaten.
What is a Cashew Apple?
A Cashew Apple is the swollen stem of the branch end above each nut. The Cashew Apple is sweet and edible. They are delicate, and are not suitable for shipping and storage. Therefore, they are not found in stores or markets.
When do Cashew Trees bloom and make nuts?
Cashew Trees bloom in spring and the fruit and nuts are ready from November through January. The nuts are ready when the fruits turn red.