How Do Cashews Grow?

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USDA Hardiness Zones 10 - 12

 

The cashew is a tropical or subtropical evergreen shrub or small tree that is native to Central and South America. The tree produces an apple or pear-shaped “accessory fruit,” known as the cashew apple, but its real fruit is the kidney shaped drupe (or stone fruit) growing at the stem of the cashew apple. The drupe is harvested, roasted, and eaten. Although it is not botanically a nut, it is commonly known as a cashew nut.

 

Cashew trees grow up to 50 feet tall, but the shrub-like dwarf version (20 feet tall at full maturity) is more popular because it produces a higher yield of cashew “nuts” and matures earlier than the full size tree. Cashew trees produce reddish pink flowers. 

 

The trees are very frost sensitive, relatively drought-resistant and fare well in sandy soils in both dry and wet tropical settings. Cashew trees that are grown from seed take up to three years to produce a harvest, but grafted trees produce in as little as 18 months.

 

Seasonal Growth

Health Benefits

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Cashews may be a tough “nut” (remember, they’re not a true nut, but instead a seed) to crack due to the caustic resin that lies between the shell and the “nut” kernel. Once they are shelled, however, cashews boast a wealth of health benefits.

 

Cashews are lower in fats than most nuts, composed of 82% unsaturated fatty acids. Of these unsaturated fatty acids, 66% are good monounsaturated fats, similar to the heart-healthy monounsaturated fats found in olive oil. When added to a low-fat diet, monounsaturated fats may help to reduce the triglyceride levels in the body, which are associated with the risk of heart disease.

 

Cashews are high in antioxidants, such as the mineral copper. One serving of cashews contains 98% the recommended daily value of copper, which is related to the elimination of free radicals in the body, cholesterol levels, skin pigmentatioin and the process of iron utilization.

 

Copper helps to stimulate the enzymes responsible for cross-linking collagen and elastin in the body, which help with flexibility in the joints, bones and blood vessels.

 

Cashews also contain almost ⅓ the daily value of magnesium, which helps to maintain healthy blood pressure by dilating blood vessels. Magnesium helps to prevent muscle cramps and spasms, soreness, muscle fatigue, migraine headaches, menopausal sleep disturbances.

 

Magnesium is also vital for bone health. In fact, about ⅔ of the magnesium found in the human body is in the bones, helping to give their physical structure. Magnesium also helps to provide muscle and nerve tone by counterbalancing calcium (which can over-activate nerve cells when in imbalance). 

 

The cardio-protective benefits, LDL (bad) cholesterol-reducing and HDL (good) cholesterol-increasing benefits of nuts, including cashews, is related to lowered risk of weight gain and obesity.

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History

 

The cashew, or acajú, as the indigenous Brazilian tribe called the Tupi named it, originates in northeastern Brazil. Colonists from Portugal introduced the cashew to the western world after discovering it in there in 1578. The cashew’s botanical name, Anacardium occidentale, is a description of their heart-like shape.

 

Via Portuguese colonization, the cashew spread to Mozambique, Africa, and later to India at the end of the 16th century. Because the cashew tree is one of the few plants that flourishes in the poor soil conditions of sandy beaches, the Portuguese originally cultivated to prevent beach erosion in coastal areas of colonization, rather than for the tree’s fruit and nuts.

 

Propagation

 

Cashew trees can be grown from seed or propagated by air layers or softwood grafts.

 

Air layering means that a strip of bark ¼ to ½ inches thick is removed from around a 9 to 12 month old pencil-thick terminal shoot.  The cut portion is covered with damp moss, wood shavings, or ordinary potting soil and wrapped tightly in polythene film.  Roots emerge from the ringed portion in 40 to 60 days when the shoot can be cut off from the parent plant and planted on its own. 

 

Softwood grafting means choosing healthy seedlings that are 50 to 60 days old to serve as rootstock. Soft wood shoots with dark green leaves of similar thickness (3 to 5 months old, non-flowering) from a high-yielding variety of cashew mother tree are grafted onto the rootstock. Successful grafts show signs of growth in 3 to 4 weeks and are ready to plant at 6 weeks.

 

Harvest

 

Cashew trees flower in winter and produce fruit for an early spring harvest. The fruits start off yellow and deepen to a deeper red--at which point they are ready for harvest.

 

Cashew apples may be eaten or juiced immediately and are not available to purchase commercially, so harvest time is the only time they’re available. Most people who grow cashew trees do so for the “nuts.” 

 

Fruits are harvested before they fall to the ground and break the cashew pod off the end of the fruit. The cashew pod can be stored for two years as-is or shelled immediately--but beware: beneath the shell lies an acidic resin that burns your skin. The oils found in a cashew shell are similar to those of poison ivy.
 

The easiest method is to freeze cashews before shelling, and to remove the nut kernel from the now solid, frozen resin.

An alternative method of shelling cashews is to roast the nuts over an open fire until the shells crack and resin drips out. The smoke created can be a toxic irritant, so roasting is usually done outdoors.

 

Storage

 

Cashews turn rancid quickly due to their high oil content. They can be stored in a cool, dry place in an airtight container, but perish in two weeks or less. Cashews can be stored in the refrigerator for up to 6 months and in the freezer for up to one year.

 

 

Fun Facts

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Vietnam, Nigeria, India, Côte d'Ivoire (The Ivory Coast), and Brazil are the top five cashew producing countries (FAOSTAT, 2011).

 

Cashews are most commonly considered for their use as food. They are eaten roasted, raw, and in salads, desserts and savory dishes. 

 

The cashew fruit (cashew apple), which is not readily available commercially in the United States, is also edible and used in fruit juices. In Goa, India, the cashew apple is mashed and the juice extracted for fermentation to be distilled into an alcoholic drink called feni. In parts of Tanzania and Mozambique in Africa, the cashew apple is also used to make strong liquors.

Cashews have a variety of non-culinary uses. Cashew shell oil is used in the development of pesticides and fungicides, antibacterials, drugs, and antioxidants. In tropical folk medicine, it is hailed for its uses as a anti-termite lumber treatment.

 

Chemicals identified in cashew oil have proven effective in defending against Streptococcus mutans, a bacteria responsible for dental cavities.

 

Because cashews are not grown commercially in the United States, few varieties are available or named. Some varieties found outside the United States include: Anakkayam, Kanaka, Dhana, Priyanka, Madakkathara, and Raghav.

 

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