How Do Peanuts Grow?

​

USDA Hardiness Zones 5 - 9

 

Most people are surprised to learn that the peanut is not a nut at all but a member of the legume, or “bean,” family. It is an annual herbaceous plant that grows 1 to 2 feet tall with the peanuts growing underground. 

 

The scientific name, hypogaea, means “under the earth” in Latin, due to the peanut’s unusual growth habit:  Above ground, the peanut plant produces yellow flowers with reddish veining. After pollination, the flower stalk elongates and bends until the ovary of the plant touches the ground and eventually, as the stalk continues to grow into “pegs”, that are pushed underground where they develop into legume pods bearing 1 to 4 seeds: peanuts.

 

Seasonal Growth

​

Health Benefits

​

Technically, peanuts may not be a nut… but that doesn’t stop us from going nuts over the health benefits of this antioxidant-rich, heart-friendly legume.

 

Peanuts play a powerful role in reducing the risk of cardiovascular disease. Studies have shown that the high levels of monounsaturated fats found in peanuts can help to reduce the risk of heart disease by an estimated 21% compared to the average American diet.

 

Due to the high content of healthy monounsaturated fats and antioxidants, enjoying a handful of peanuts or a tablespoon of natural peanut butter four times per week may significantly reduce the risk of cardiovascular disease.

 

Peanuts are also good sources of oleic acid (the heart-healthy fat found in olive oil), niacin, folates, vitamin E, manganese and protein-- all of which are nutrients shown to promote heart health.

 

Peanuts are a great source of antioxidants--especially when they’ve been roasted. Studies conducted by scientists at the University of Florida show that roasting peanuts increases the levels of p-coumaric acid, a polyphenol, boosting peanuts’ antioxidant content by as much as 22%. 

 

Resveratrol, a phenolic antioxidant found in peanuts, is also found in red grapes and red wine. It is thought to be responsible for the “French Paradox”: Although the French diet is not low in fat, there is a lower risk of cardiovascular disease there than in the United States due to their increased wine consumption.

 

Resveratrol has been determined to improve blood flow to the brain by as much as 30% in animal studies. Routine consumption of peanuts may be valuable in reducing the risk of stroke.

 

Peanuts are also very rich in niacin. Studies have shown that niacin-rich foods such as peanuts are important in the prevention of Alzheimer’s disease and other age-related cognitive decline.

 

Antioxidants found in peanuts may also reduce the risk of certain cancers--most specifically, colon cancer. One study found that consuming a serving of peanuts just two times per week reduced the risk of colon cancer by 58% for women and 27% for men.

​

History

​

Peanuts originated in South America, likely in the area around Peru or Brazil. The oldest specimens date back 7600 years. South American art dating back approximately 3500 years depicts images of peanuts, and archaeological evidence suggests that the Incans offered peanuts as sacrificial offerings and buried them with their dead as early as 1500 BCE.

 

European settlers first encountered peanuts upon the Spaniards’ arrival in South America in the 16th century. Upon their return to Europe, they brought peanuts with them, where they were cultivated.  Eventually they made their way to North Africa and Asia. Africans were the first to bring peanuts with them to North America in the 1700s.

 

In the early 1800s, farmers in the southern U.S. began to grow peanuts commercially on a relatively modest scale. It was not until the early 20th century that peanuts gained the popularity they enjoy today. 

 

Dr. George Washington Carver began researching peanuts in 1903 as a rotation crop for cotton farmers. He suggested that by rotating crops, peanuts would replace the nitrogen that cottons crops depleted from the soil. Carver also developed more than 100 commercial products, including domestic and farming products, cosmetics, gasoline, dyes, nitroglycerin and paints using peanuts.  He also wrote a practical bulletin for poor farmers that listed 105 recipes for peanuts, and taught how to use peanuts as both food and for other purposes.

 

Peanuts became an integral part of American culture during World Wars I and II, when they were a portable and popular source of protein for soldiers. Most notably, the peanut butter and jelly sandwich is thought to have originated during World War II, when it became a food staple for our troops.

 

Today, the United States is one of the top producers of peanuts in the world.

 

Propagation

 

Peanuts are planted after the last frost in spring for a fall harvest.

 

They are propagated easily by seed, by shelling  and sowing raw, uncooked peanuts. Roasted peanuts will not grow.

 

Peanuts are considered a southern, warm-weather crop but some varieties can be grown as far north as southern Canada. The plant has a long growing season, typically ranging from 100 to 150 frost-free days. Early maturing varieties are grown in the north and often started as seedlings indoors 1 to 2 months prior to sowing outdoors. 

 

Harvest

 

Peanuts are harvested when the plant has turned yellow, before the first frost. 

 

The entire plant is dug up, cleaned of dirt and hung to dry.

Alternatively, the peanut pods are cut from the plant and placed to dry in a warm space.

 

Peanuts need to dry for approximately two months following harvest before they are ready to eat. The largest and best-formed peanuts are saved to propagate the following year’s crop.

 

Storage

 

Unshelled peanuts can be stored up to two months in an airtight container in a cool, dry place. Because of their high oil content, they need to be stored properly so that they do not become rancid.

 

To keep peanuts longer, store unshelled peanuts in the refrigerator (4 to 6 months) or in the freezer (9 to 12) months in an airtight container.

 

Fun Facts

 

The world’s top producers of peanuts are: China, India, the United States, Nigeria and Indonesia (FAOSTAT, 2010).

​

Peanuts are eaten raw or roasted. Peanut butter is the most common product made from peanuts and is used in a variety of ways, the most popular, or course, being the peanut butter and jelly sandwich.

 

Peanuts and sauces made from peanuts are used in a number of traditional Asian and Asian-American dishes, including Thai and Chinese cuisine. They are also ingredients in a number of desserts, candies, breakfast foods and more. 

 

Outside of its myriad culinary uses, peanuts are also used to make household items including paper, various kinds of oils, hand cleansers, laundry soaps, cosmetics, and medicines.

 

Peanuts in the United States fall into four different categories:

 

Runners, the dominant variety, account for more than 80% of the peanuts grown in the United States. 

 

Virginia peanuts have the largest kernels, accounting for most of the salted and roasted in-shell peanuts sold--and account for about 15% of the peanuts grown in the U.S. 

 

Spanish varieties have smaller kernels with reddish-brown skin. Commercially, they are primarily used in candies and for making oils. They make up 4% of the peanuts grown in the U.S.

 

Valencia is the sweetest variety, usually roasted and sold in its shell or used for boiling. They account for less than 1% of the peanuts produced in the United States.

 

Grow it Yourself:

 

Peanuts are generally considered a warm weather southern crop but can be grown with success in northern climates. 

 

To successfully grow peanuts in a northern climate, The “Old Farmer’s Almanac” advises choosing an early-maturing variety such as “Early Spanish,” and to plant on a south-facing slope, if possible. 

 

1. Plant peanuts in spring after the danger of the last frost. In southern climates, this may be as early as March but in northern climates, as late as the third or fourth week of April. In northern climates, peanuts may be started indoors 5 to 8 weeks prior to planting to get a jumpstart on the growing season.

 

To start indoors, fill a large, four-inch deep bowl ⅔ full of moist potting soil. Shell four fresh, unroasted peanuts and place them on top of the soil, covering with one inch of soil. Seedlings will sprout quickly. Transplant outdoors when danger of frost has passed and average soil temperatures reach 60 to 65 degrees.

 

To start peanuts outdoors, choose a sunny location and prepare a bed of sandy, well-draining soil mixed with loose, organic compost. 

 

2. To plant:  In southern climates, place peanut seeds (unroasted, shelled peanuts) at least two inches deep, spaced 8 inches apart. In northern areas, plant one inch deep to prevent root rot in damp spring climates. If needed, protect young plants from frost with plastic covering.

 

3. When plants reach 6 inches high,  loosen the soil around the plant so the flower pegs will penetrate it easily. Mulch with two inches of straw or grass clippings.

 

4. Small yellow flowers will grow along the stem, and after they fade the ovaries will begin to swell and grow toward the ground in shoots called “pegs”, eventually pushing into the soil. This process takes about ten days.

 

Harvest in fall when the plant yellows, before the first frost.