How to Grow Cashew Trees

The cashew tree (Anacardium occidentale) is native to Brazil but today it is cultivated in many Asian and African countries. Cashew nuts are delicious and rich in many essential nutrients. These are nothing but the seeds of the cashew plant. The cashew plant bears attractive fruits and each fruit yields a single cashew nut. If you look at the fruit of the cashew tree, you'll see that it is pear-shaped with a kidney-shaped shell attached to the bottom. However, on close inspection, you shall find that the pear-shaped part is not the fruit but the pedicel that joins the fruit to the plant. It is referred to as the cashew apple and is reddish in color. Now, the cashew apple is not only edible, but also juicy and high in nutritive value. It is rich in vitamin C, vitamin B₁, calcium and iron. Now, coming to the shell that encloses the cashew nut: it is filled with a liquid that is caustic in nature i.e., it can cause burns on your skin. The cashew that we eat is nothing but the dried kernel. Cashew shell oil is obtained from the corrosive liquid and is used for treating wood.

Growing Cashew Trees

You'd be glad to know that cashew trees are easy to grow and hardly require a lot of maintenance. All you need to do is ensure that you keep the climatic requirements in mind before going ahead with growing a cashew tree. Here, you'll find all things you need to know to cultivate delicious cashews in your garden or backyard.

Factors Affecting the Growth of Cashew Trees

Temperature
The first thing that you should consider before planting a cashew tree, is the climate in your region. Since, the cashew is a tree that grows in the tropics, it is very sensitive to frost and is unable to survive temperatures below 10°C or 50°F. The average temperature should ideally be around 27°C or 80°F. However, high temperature is not a problem with cashew trees that are capable of withstanding temperatures as high as 40°C or 105°F and are also fairly resistant to drought.

Rainfall
Cashew trees can withstand dry spells but not too much rainfall. In fact, heavy rainfall can damage the flowers, which get affected by mildew. Also, rainfall during the harvesting season can cause the nuts to rot or cause the fallen nuts to start germinating. Experts believe that an average annual rainfall of 1000-1500 mm is sufficient for the growth of cashew trees.

Soil
Sandy soil that does not retain water, is ideal for growing cashew trees. These trees cannot withstand accumulated water around the roots and hence, cannot grow in clay soils. Fertilizers containing nitrogen and phosphorous are good for the plant, especially before it is time for the plants to bear flowers.

In addition to the above factors, you should also see to it that the plant you are growing is protected from strong winds.

How to Plant Cashew Trees

There are two methods of growing cashew trees - you can either plant a seed or a grafted tree. Growing a grafted tree is mostly preferred because it ensures that the plant takes on the characteristics of the parent plant. A major drawback of growing cashew trees from seeds is that the plants growing from seeds mostly don't resemble the parent plant in characteristics and hence are not "true to type".

If you wish to grow cashew trees from seeds, get fresh seeds and plant them in sterilized soil contained in a plastic bag. Plant the seeds such that the stalk end of each seed is facing upwards and there is a minimum distance of 30-40 cm between them. Remember, cashew trees need plenty of room to spread their roots and planting them too close to one another will hamper their growth. Dig holes that are 5 cm deep and plant three or four seeds in each hole. Water the seeds regularly for optimum growth. As the seedlings develop, let the strongest one remain and weed out the others. Once the seeds germinate after 10-12 days, you can gently remove the seedlings and transplant them to your garden.

Preparing the soil is essential before planting seedlings or grafts of the cashew plant. For this, you need to remove weeds, grasses and other debris from the plot. Also, the holes that you dig should be at least 10-15 cm deep to allow the root to develop. It is important to note that cashew trees need a surrounding area of 30 square feet to grow, which means that you need to plant the seedlings at least 30 feet or 10 m apart.

How to Care for Your Cashew Trees

Just like with any other plant, planting a cashew tree alone is not enough. To ensure that your tree stays healthy and grows properly, you need to take a few steps. Cashew trees grown from seeds start to bear fruit after three years while those grown from grafts, bear fruit within 18 months. Given below are a few important pointers on how to care for a cashew tree.

• Water the cashew trees regularly (at least once a week) till they are mature. This is because the plant needs adequate water till the time its root system is fully developed. Once the tree is fully grown, however, it can survive with very little water.
• Fertilizing is also essential for proper growth of the trees. Use a fertilizer that is composed of nitrogen, phosphorous and potassium and fertilize the trees when they blossom and again when the fruits begin to appear. If you have any queries regarding the exact quantity of fertilizer to be used, depending on the soil in your region, you can consult a horticulturist.
• Young cashew trees are tender, and so it is recommended that you bind them to wooden stakes for support.
• Cashew trees are prone to zinc deficiency, so use a zinc leaf spray regularly.
• Prune the trees on a regular basis to remove dead and diseased branches, if any.

When you see that the cashew apples have turned dark pink or red in color and the shell has turned a darker shade of gray, know that it is time for harvesting. Once the fruits are plucked, the nuts should be dried and stored. Commercially processed cashews are subjected to a number of steps to obtain the edible kernel, which is then packed and marketed. Cashew trees can grow to a maximum height of 40 feet and they produce maximum yield only after the seventh year.