Peanuts and the south go together like wine and cheese or gumbo and French baguette.The peanut (Arachis hypogaea), also known as the groundnut, goober, or monkey nut, is a legume crop grown mainly for its edible seeds. It is a common crop in the tropics and subtropics worldwide grown as a grain legume for its seeds and as an oil crop due to the high oil content in the seed (45-52%). Over 50,000 metric tons are produced annually worldwide. The top peanut producers are China (37%), India (13%), Nigeria (9%), US (5%), and Sudan (5%). The US produces over 2500 metric tons annually. In other parts of the world, peanuts are also grown as a forage crop. Peanuts are grown commercially in 13 states: Alabama, Arkansas, Florida, Georgia, Louisiana, Missouri, Mississippi, North Carolina, New Mexico, Oklahoma, South Carolina, Texas and Virginia. Top producers are Georgia (50%), Florida (11%), Alabama (10%), Texas (9%), North Carolina (8%), and South Carolina (4%). The remaining 7 states produce 8% combined.

The Arachis genus is native to South America. The current theory is that the cultivated species (Arachis hypogaea) came from a onetime chance hybridization of two wild species that gave rise to a sterile hybrid. A chance spontaneous chromosome doubling restored fertility to the hybrid with selection and domestication resulting in the emergence of the current cultivated species. The domesticated plants are bushier, more compact, and have a different pod structure and larger seeds than the wild types.

Peanuts and peanut products have many commercial industrial uses. Some products from peanuts include: peanuts, peanut butter, peanut flour, peanut oil, hay (tops), and mulch (shells).

Nutritional Value

Peanuts are highly nutritious and an important part of many diets worldwide. They are high in protein and healthy fats (see Table 1: Nutritional Content). They also contain other healthy nutrients, minerals, antioxidants and vitamins.

There have been lots of studies on other health benefits of peanuts which includes improved gut microbiome, heart-healthy fats that lower LDL (bad) cholesterol, reduced risk of cardiovascular disease, reduced risk of weight gain, low glycemic index that reduces inflammation, reduced blood pressure, and reduced risk for type 2 diabetes. They also contain resveratrol which studies show health benefits of anticancer, antimicrobial, neuroprotective, antiaging, anti-inflammatory, cardioprotective and blood-sugar lowering properties. These studies are usually done with peanuts that still have their skin because many of the active compounds are concentrated in the skin.

Botany

Arachis hypogaea is a member of the Fabaceae family commonly known as legumes. The peanut is not a nut at all but the seed of a legume. It would be more accurately called a bean or pea. Arachis comes from the Greek word meaning pea or vetch. The Greek derivation of hypogaea means “under earth”, the fruits are produced underground.

The peanut is an herbaceous annual with opposite, pinnately compound leaves having four leaflets ½” – 2 ¾” long by ½” – 1 ¼” wide depending on variety. Like many legumes, the leaflets fold shut at night and open in the morning.

The 3/8” to 5/8” wide flowers are yellowish orange with reddish veins and borne in axillary clusters above ground. The self-pollinating flowers last for only one day.

Peanut fruits develop underground, an unusual process known as geocarpy. The fertilized ovary begins to elongate and grows downward from the node to the soil. This specialized structure, called a peg, becomes visible about 7 days after fertilization. The sharp-pointed peg enters the soil about 10 to 14 days after pollination. The developing pod is located in the tip of the peg. Once in the soil, it begins to enlarge and forms the pod and kernels. The pod will not begin growth until the peg is in darkness. Because several flowers can develop from each node, several pegs and pods can be found originating from a single node. These pods are 1 to 3 in. long, normally containing one to four seeds. The size and number of peanuts is variety dependent. The mesocarp becomes a hard shell with several large veins traversing its length. The indeterminate fruiting habit of the peanut means the plant will have pods of varying maturity. Consequently, peanut harvest determinations are based on the presence of 70 to 80 percent mature pods.

Mature, harvestable pods require 60 to 80 days of development. Temperature (both day and nighttime) interacts with variety, planting date, seasonal moisture, etc., in controlling development of the crop. However, the controlling factor in all plant development is temperature.

Site

Peanuts grow best in well-drained, light, sandy loam soil with a pH of 5.9–7.0. Peanuts do not grow well in compacted or high clay soils. Peanuts need 8 or more hours of direct sunlight daily for optimal growth.

Planting

Seeds should be planted in a well-prepared seedbed in soil that is loose and crumbly with no large clumps. Plant seeds 1.5 to 3 inches deep when soil temperatures are consistently above 65^oF. Plants grow optimally at temperatures between 86 and 93^oF although they will tolerate a range between 59 and 113^oF. Temperatures above 93^oF may damage flowers.

Sow 4-6 seeds per foot of row. Seeds germinate and plantlets emerge 5-10 days after planting. When plants are 2” tall, thin to 8-12” apart. Depending on variety, plants will spread 2.5-3.5 feet. Space the rows at least 20 inches apart. Keep the soil moist after planting to ensure uniform germination. Peanuts transplant well and can be started indoors 3-4 weeks before transplanting out.

You need 10-12 plants per person. Each plant yields 25-50 nuts.

Culture

Keep plants well-watered during dry periods to promote rapid, uninterrupted growth. Plants need about 1 inch of rain per week during the growing season. Keep the soil moist but not saturated. Peanuts are resistant to drought and can withstand long periods without water, but this will cause a reduction in yield.

Like all legumes, peanuts form a symbiotic relationship with Rhizobium bacteria. These bacteria form nodules on peanut roots and fix atmospheric nitrogen making it available for their host. Legume Rhizobium inoculant is available commercially. If peanuts nodulate properly, they have little need for addition of nitrogen fertilizer. Leaf yellowing may indicate a need for nitrogen. Peanuts require calcium in the soil for good pod fill. The calcium in the soil is absorbed directly by the pods in the pegging zone. Soil tests will be a good guide to what nutrients, if any, you need to add for good peanut growth. Phosphorus or potassium deficiencies may require the addition of super triple phosphate or muriate of potash.

Harvest

Depending on the variety and weather, peanuts usually reach the harvestable stage 85-130 days after planting. As mentioned in the Botany section, peanuts continually flower and fruit. Harvesting is timed when 70-80% of the pods are mature. Upon harvest, you will have around 20% of the pods still immature.

To harvest, remove the entire plant from the ground. Loosen the soil with a garden fork around the plant prior to pulling so the pods will remain attached. Shake off the excess soil and hang plants to sun dry for 4-7 days. Then remove the pods, spread in a single layer and allow to cure for 2-3 weeks in warm well-aerated space before storing. Peanuts are cured when the outer shell is hard and brittle.

Alternatively, remove the pods immediately after pulling and spread to dry and cure. You can rinse the soil from the pods after removing from the plant and then spread to dry and cure.

If you plan to use the peanuts for boiled peanuts, they should be harvested and boiled prior to curing.

Pollination

Self-pollination means peanuts do not require outside aid such as bees, other insects, or the wind to transfer pollen from one plant to another for fertilization. However, flowers may be visited by pollinators in search of nectar.

Peanut Types and Production

U.S. peanuts fall into four basic types: Runner, Virginia, Spanish and Valencia. Each of these peanuts is distinctive in size and flavor.

Runner (Arachis hypogaea subsp. hypogaea)

Runners have become the dominant peanut type grown in the U.S. due to the introduction of the Florunner variety in the early 1970s, which was responsible for a spectacular increase in peanut yields. Runners have rapidly gained wide acceptance because of their attractive kernel size range; a high proportion of runners are used for peanut butter. Runners, grown mainly in Georgia, Alabama, Florida, Texas and Oklahoma, account for more than 85% of total U.S. production.

Some runner type varieties are: Bradford Runner, Early Runner, Egyptian Giant, Florunner, Sunrunner, Southern Runner, Georgia Runner, Georgia Green, Flavor Runner 458, Rhodesian Spanish Bunch.

Virginia (Arachis hypogaea subsp. hypogaea)

Virginias have the largest kernels and account for most of the peanuts roasted and eaten as inshells. When shelled, the larger kernels are sold as salted or flavored peanuts. Virginias are grown mainly in southeastern Virginia and northeastern North Carolina, South Carolina and West Texas. Virginia-type peanuts account for about 10% of total U.S. production.

Some common Virginia type varieties are: Bailey, Champs, Florida Fancy, Gregory, Perry, Phillips, Sugg, Sullivan, Titan, Wynne.

Spanish (Arachis hypogaea subsp. fastigiata)

Spanish-type peanuts have smaller kernels covered with a reddish-brown skin. They are used predominantly in peanut candy but are also used for salted nuts and peanut butter. Spanish peanuts have higher oil content than the other types of peanuts, which is advantageous when crushing for oil. The Ole Spanish variety was released in 2015 after extensive research and is high in oleic acid, a beneficial monounsaturated fatty acid; its high roasted peanut score and increased shelf life make it ideal for candy bars or for snack nuts. Spanish-type peanuts account for 2% of U.S. production.

Some common Spanish type varieties are: Argentine, Comet, Dixie Spanish, Florispan, Georgia 045, Hull, Ole Spanish, Olin, Pronto, Shulamit, Spanco, Tamspan 90.

Valencia (Arachis hypogaea subsp. fastigiata)

Valencias usually have three or more small kernels to a pod. They are very sweet peanuts and are usually roasted and sold in the shell; they are excellent for fresh use as boiled peanuts. Valencias are also commonly used to make natural peanut butter. Due to greater demand for other varieties, Valencias account for less than 1% of U.S. production and are grown mainly in New Mexico.

Some common Valencia type varieties are: GenTex 118, GenTex 136, Georgia Red, Georgia Valencia, Nu-Mex 01,Tennessee Red, Valencia A, Valencia C.

Common Diseases

(ALWAYS read and follow label instructions on pesticides).

Late Leaf Spot (Cercosporidium personatum): Late leaf spot causes dark brown to black leaf spots (lesions) that penetrate through the leaf and are visible on both the upper and lower leaf surface. The spots may (or may not) be surrounded by a yellow halo. Young late leaf spot lesions appear as dark speckles while older lesions are rounded and dark brown to nearly black. Late leaf spot lesions produce masses of spores in humid weather. On the underside of the leaf, the dark mass of spores on the lower lesion surface gives the spot a velvety appearance that can be seen without magnification. Control: Crop rotation is recommended. Fungicides containing chlorothalonil or thiophanate methyl are effective.

Early Leaf Spot (Cercospora arachidicola): Early leaf spot typically causes penetrating brown lesions (spots) visible on the upper and lower leaf surface. A yellow halo usually is present around early leaf spots, but halos are NOT diagnostic since they also are common with late leaf spot. The difference between the brown lesions of early leaf spot and the dark-brown-to-black lesions of late leaf spot is most apparent on the lesions viewed on the underside of the leaf. Early leaf spot lesions are generally round, but can expand or grow together, becoming less regular in shape. The fungus produces tufts of silvery, hair-like spores on lesions during humid weather. Control: Crop rotation is recommended. Fungicides containing chlorothalonil or thiophanate methyl are recommended.

Stem Rot (Sclerotium rolfsii): Southern blight, also known as stem rot, is caused by a soilborne fungus.The disease is widespread on peanuts and other crops in Louisiana.Disease development is favored by hot and humid conditions in the peanut canopy. Therefore, the disease occurs mainly in mid- to late-season. The fungus primarily attacks the base of stems near the soil line, but any plant part in contact with soil may be damaged. Infected plants are generally killed prior to maturity. Peg and pod infections are common and result in pod loss at harvest. Control: Fungicides containing tebuconazole are recommended.

Limb Rot (Rhizoctonia solani): Limb rot usually appears in late August and September after the vines of runner varieties have lapped. Elongated spots (lesions) develop on the underside of lower branches in contact with the soil. The lesions are dark brown and may have a target-like appearance. Lesions expand and girdle individual branches causing them to wilt and die. In severe cases where rainfall is excessive, leaves within the canopy are covered with a white, moldy growth. Control: Fungicides containing tebuconazole are recommended.

Rust (Puccinia arachidis): Characteristic orange pustules appear on undersides of leaves which become covered in masses of red-brown spores; pustules may form on pods. Peanut rust is highly specific to peanut; disease emergence and spread is favored by warm temperatures followed by leaf wetness. Control: Fungicides containing tebuconazole or azoxystrobin are recommended.

Common Pests

(ALWAYS read and follow label instructions on pesticides).

Cowpea Aphid (Aphis craccivora): Cowpea aphids have a broad host range with a preference for legume crops. Cowpea aphids are relatively small, ranging from 1.5 to 2.5 mm long. Adults may be winged or wingless and are usually shiny black, while nymphs are smoky gray. They tend to feed in clusters on newly expanding leaves, blooms, and stems. Infested plants become yellowish, stunted, and non-productive because of direct feeding and the insects’ toxic salivary secretions. Cowpea aphids are efficient vectors of several important virus diseases. Control: Introduce or attract natural predators into your garden such as lady beetles and wasps which feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap. Horticultural oils are also effective as are insecticides containing bifenthrin, permethrin or imidacloprid.

Corn earworms (Helicoverpa zea) and tobacco budworms (Helicoverpa armigera) vary in color from light green to almost black. They are one of the most common caterpillars that feed on peanut foliage. The life cycle requires about 30 days, with 14 to 16 days of this time spent in the larval stage. There may be several generations in peanuts during a single growing season. Control: Soft pesticides like Bt and Spinosad are effective against these caterpillars. Traditional insecticides containing bifenthrin or permethrin are also recommended.

Armyworms (Spodoptera spp.): Armyworm feeding leaves singular, or closely grouped circular to irregularly shaped holes in foliage. Heavy feeding by young larvae leads to skeletonized leaves. Egg clusters of 50-150 eggs may be present on the leaves; egg clusters are covered in a whitish scale which gives the cluster a cottony or fuzzy appearance. Young larvae are pale green to yellow in color while older larvae are generally darker green with a dark and light line running along the side of their body and a pink or yellow underside. This varies slightly within the fall armyworm, beet armyworm, yellow-striped armyworm group. Control: Soft pesticides like Bt and Spinosad are effective against armyworms. Traditional insecticides containing bifenthrin or permethrin are also recommended.

Velvetbean caterpillar (Anticarsia gemmatalis): The larva causes damage to plants by feeding on leaves. The larva skeletonize the leaves by feeding only on soft parts. Later stage larvae consume entire leaves. They will stripe the plants in a few days. The larvae also feed on tender stems, buds and pods. Control: Soft pesticides like Bt and Spinosad are effective against velvetbean caterpillars. Traditional insecticides containing bifenthrin or permethrin are also recommended.

Threecornered Alfalfa Hopper (Spissistilus festinus): The threecornered alfalfa hopper adult is a green, wedge-shaped insect with clear wings. The body is about 0.25 inch long, is higher and wider at the head and tapers towards the end. This insect gets its common name from the triangular area over the thoracic area as seen from above. It has piercing-sucking mouthparts. Nymphs are grayish white and soft bodied, with a line of saw-toothed spines on their backs. Adults and nymphs of the alfalfa hopper usually feed at the base of the plant near the crown. This makes the stem prone to breaking easily and interferes with nutrient movement in the plant. Damaged stems will often turn a deep purple color. Three-cornered alfalfa hoppers will also feed on the pegs. Control: Insecticides containing bifenthrin, carbaryl, or beta-cyfluthrin have been recommended.

Thrips: Thrips are tiny needle-thin insects that are black or straw colored. They suck the juices of plants and attack flower petals, leaves and stems. The plant will have a stippling, discolored flecking or silvering of the leaf surface. There are several species of thrips that can be found on peanuts, most commonly the tobacco thrips (Frankiella fusca) and the western flower thrips (Frankliniella occidentalis). Tomato Spotted Wilt Virus is a thrips vectored viral disease. Control: Insecticidal soaps and horticultural oils will work with good coverage. Spinosad is more effective and longer lasting. Insecticides containing imidacloprid are also effective.

Two-spotted spider mite (Tetranychus urticae): They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Control: Insecticidal soaps and horticultural oil are recommended contact pesticides.

What About Peanut Allergies

I would be remiss if I didn’t also mention peanut allergies. Peanut allergies are one of the most common and potentially dangerous food allergies, affecting at least 1% of the U.S. population and anywhere from 2% to 5% of children. Year after year, peanut allergies continue to climb, particularly among children previously unexposed to peanuts.

Because of this, the FDA has instructed food manufacturers to prominently list peanuts—along with any of the seven other common allergens (milk, eggs, fish, shellfish, tree nuts, wheat, and soybean)—on product labels. Some manufacturers may include wording like "may contain peanuts" if the product is produced in a facility that uses nuts in other food products. This can help you avoid hidden nuts if you are especially allergic. Peanut allergies are most often a reaction to proteins in peanuts, the most common of which are arachin and conarachin.

Peanut allergies can range from mild to life-threatening. In rare instances, it can lead to an all-body reaction known as anaphylaxis, characterized by a severe rash or hives, shortness of breath, wheezing, rapid heart rate, the swelling of the face or throat, and a "feeling of impending doom." If left untreated, anaphylaxis can lead to shock, coma, heart or respiratory failure, and death.

Although many parents are terror-struck by the very notion of a peanut allergy, the American Academy of Allergy, Asthma, and Immunology recommends that peanuts be introduced into a child's diet early to sensitize them to peanuts and avoid the development of an allergy. Research shows that early peanut introduction in a child’s life (between age 4-6 months) can reduce peanut allergy risk by 86%.

Peanut Tidbits

1. It takes about 540 peanuts to make a 12-ounce jar of peanut butter.

2. By law, any product labeled “peanut butter” in the United States must be at least 90 percent peanuts.

3. It takes 3.2 gallons of water to produce 1 ounce of peanuts. (Bonus fact: 1 ounce of almonds takes 28.7 gallons)

4. The average person will eat almost 3,000 PB&Js in their lifetime, according to a 2016 survey by Peter Pan Simply Ground Peanut Butter.

5. The Huffington Post (Sept. 2014) asked, “What makes the best peanut butter and jelly sandwich? Results show: 36% say strawberry jam is favorite (grape is 31%); favorite bread is white bread (54%); favorite type of peanut butter is smooth (56%) and a whopping 80% like their PB & J with the crust left on the sandwich.

6. Two peanut farmers have been elected president of the USA – Virginia's Thomas Jefferson and Georgia's Jimmy Carter.

7. Former President Bill Clinton says one of his favorite sandwiches is peanut butter and banana; also reported to have been the favorite of Elvis “the King” Presley.

8. There are six cities in the U.S. named Peanut: Peanut, California; Lower Peanut, Pennsylvania; Upper Peanut, Pennsylvania; Peanut, Pennsylvania, Peanut, Tennessee; and Peanut West Virginia.

9. Goober—a nickname for peanuts—comes from “nguba”, the Congo language name for peanut.

10. George Washington Carver was known as the “plant doctor” and the “grandfather of peanuts”. He discovered many ways to use peanuts and innovative farming methods, including crop diversification and soil conservation.

11. There are enough peanuts in one acre to make 35,000 peanut butter and jelly sandwiches.

12. Peanuts are naturally cholesterol-free. They’re a great plant-based option, contain more protein than any nut and several essential vitamins and minerals.

13. Peanuts are the most sustainable nut. From the roots to the hulls, no part of the plant goes to waste. They also have the most efficient water use carbon footprint.

14. Peanuts are the 7th most valuable crop in the US.

15. Have you ever wondered where the term “Peanut Gallery” comes from? The expression, which became popular in the late 19th century, refers to the section of cheap seats in a theater or the group of spectators seated there.

16. Mr. Peanut was created by 13-year-old Antonio Gentile in a logo contest held by Planters in 1916. He won the grand prize of $5.00. His drawing of a peanut person with arms and crossed legs was refined by a professional illustrator who added the top hat, monocle, white gloves, and cane.

17. Peanuts account for two-thirds of all snack nuts consumed in the U.S.

18. March is National Peanut Month; November is National Peanut Butter Lovers’ Month.

Selected References

10 Interesting Facts About Peanut. 2016. 10 interesting facts about peanut – PASOKIN

25 Fun Facts About Peanuts & Peanut Butter. 2022. National Peanut Board. 25 Fun Facts about Peanuts & Peanut Butter | National Peanut Board

6 Ways Peanuts Can Help Your Heart. 2022. The Peanut Institute. https://peanut-institute.com/6-ways-peanuts-can-help-your-heart/

Arnarson, A. 2023. Peanuts 101: Nutrition Facts and Health Benefits. Healthline.com. Peanuts 101: Nutrition Facts and Health Benefits (healthline.com)

Damicone, J.P. 2017. Foliar Diseases of Peanuts. OSU Extension. Foliar Diseases of Peanuts | Oklahoma State University (okstate.edu)

LaJeunesse, S. 2022. Peanuts and herbs and spices may positively impact gut microbiome. PSU Extension. https://www.psu.edu/news/research/story/peanuts-and-herbs-and-spices-may-positively-impact-gut-microbiome/#:~:text=Two%20studies%20show%20that%20adding,health%2C%20according%20to%20new%20research.

Lehmen, Shereen. 2022. Peanut Nutrition Facts and Health Benefits. https://www.verywellfit.com/peanuts-and-peanut-butter-are-good-for-your-diet-2506569#:~:text=Peanuts%20are%20nutrient%2Ddense%20and,thiamin%20(16%25%20DV).

Peanut Country, USA. 2019. National Peanut Board. https://www.nationalpeanutboard.org/peanut-info/peanut-country-usa.htm

Peanut Explorer. 2022. USDA. https://ipad.fas.usda.gov/cropexplorer/cropview/commodityView.aspx?cropid=2221000

Peanut Nutrition Facts. 2023. Peanuts, raw, all types nutrition facts and analysis. (nutritionvalue.org)

Peanut Nutrition Facts. 2023. The Peanut Institute. https://peanut-institute.com/peanut-facts/nutritional-breakdown/

Plant Growth and Development of Peanuts. Plant Growth and Development of Peanuts (soilcropandmore.info)