Peanut (Arachis hypogaea) is an annual plant belonging to the Fabaceae family, commonly known by various names such as Goober Peas, Groundnut, Monkey Nut, Pindar, and Virginia Peanut. Native to Central Brazil, this legume is widely cultivated for its edible seeds and oil. The plant typically grows to a height of 46 to 61 cm, producing golden yellow flowers in spring. After flowering, the seed pods develop underground, a unique characteristic of peanuts. Known for their versatility, harvested peanuts are used in numerous products, including food and oil, making them a valuable crop worldwide.
| Common name | Goober Peas, Groundnut, Monkey Nut, Peanut, Pindar, Pygmy Nut, Virginia Peanut |
| Botanical name | Arachis hypogaea |
| Family | Fabaceae |
| Species | hypogaea |
| Origin | Central Brazil |
| Life cycle | Annual |
| Plant type | Annual |
| Hardiness zone | 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 |
| Sunlight | Full Sun |
| Maintenance | Medium |
| Soil condition | Clay |
| Soil ph | Acid |
| Drainage | Well-Drained |
| Spacing | 12 in. – 3 ft. |
| Harvest time | Fall |
| Flowering period | Summer |
| Height | 9 in. – 1 ft. 6 in. |
| Flower color | Gold, Yellow |
| Leaf color | Green |
| Fruit color | Brown, Copper |
| Stem color | Green |
| Fruit type | Legume |
| Fruit benefit | Edible |
| Flower benefit | Showy |
| Garden style | Edible Garden |
I. Appearance and Characteristics
The peanut (Arachis hypogaea), also known as the groundnut, goober (US), goober pea, pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible seeds. It is widely grown in the tropics and subtropics, important to both small and large commercial producers. It is classified as both a grain legume and, due to its high oil content, an oil crop. Atypically among legume crop plants, peanut pods develop underground (geocarpy) rather than above ground. With this characteristic in mind, the botanist Carl Linnaeus gave peanuts the specific epithet hypogaea, which means “under the earth”.
The peanut belongs to the botanical family Fabaceae (or Leguminosae), commonly known as the legume, bean, or pea family. Like most other legumes, peanuts harbor symbiotic nitrogen-fixing bacteria in root nodules. The capacity to fix nitrogen means peanuts require less nitrogen-containing fertilizer and improve soil fertility, making them valuable in crop rotations.
The botanical definition of a nut is “a fruit whose ovary wall becomes hard at maturity.” Using this criterion, the peanut is not a nut. However, peanuts are usually categorized as nuts for culinary purposes and in common English more generally. Peanuts are similar in taste and nutritional profile to tree nuts such as walnuts and almonds, and, as a culinary nut, are often served in similar ways in Western cuisines. World production of shelled peanuts in 2020 was 54 million tonnes, led by China with 34% of the total.
Peanut plants are a common food crop around the world, but to certain people, their nuts are actually dangerous and potentially deadly. Peanut allergy is one of the more common and extreme allergies out there, and can potentially kill. It is becoming more common, and those who suffer from it most tend to be children. It contains certain proteins in its seeds, seed “skins,” and seed oils that trigger the reaction.
Symptoms include rashes on skin contact, nausea, stomach upset, chills and vomiting if eaten, and asthma symptoms if peanut dust is inhaled. Even traces of the nuts, say from cross-contamination, can cause a reaction. In severe cases, life-threatening anaphylactic shock can occur. If anyone in your household has a peanut allergy, do not grow them in your garden.
Peanuts grow best in light, sandy loam soil with a pH of 5.9–7. Their capacity to fix nitrogen means that providing they nodulate properly, peanuts benefit little or not at all from nitrogen-containing fertilizer, and they improve soil fertility. Therefore, they are valuable in crop rotations. Also, the yield of the peanut crop itself is increased in rotations through reduced diseases, pests, and weeds. For example, in Texas, peanuts in a three-year rotation with corn yield 50% more than non rotated peanuts. Adequate levels of phosphorus, potassium, calcium, magnesium, and micronutrients are also necessary for good yields. Peanuts need warm weather throughout the growing season to develop well.
They can be grown with as little as 350 mm (14 in) of water, but for best yields need at least 500 mm (20 in). Depending on growing conditions and the cultivar of peanut, harvest is usually 90 to 130 days after planting for subspecies A. h. fastigiata types, and 120 to 150 days after planting for subspecies A. h. hypogaea types. Subspecies A. h. hypogaea types yield more and are usually preferred where the growing seasons are sufficiently long.
II. How to Grow and Care
Sunlight
Peanuts grow best in areas with lots of full sun—at least eight hours daily.
Temperature and Humidity
Peanuts grow best in high heat and high humidity. The soil must reach 65°F-70°F for germination. After that, the plants grow best in a range of 85°F-95°F. When nighttime temperatures fall for several days, the soil temperature might drop to 65°F or lower, at which point the peanuts stop maturing.
Watering
Peanuts need about 1 inch of rain or irrigation per week during the growing season. Watering is most critical immediately after planting, to ensure germination and establishment of the seedlings, then again 60 to 110 days after planting when the pegs have entered the soil and are filling with peanut clusters. Stop watering the plants 10 days to two weeks before harvesting.
When watering, avoid wetting the leaves and use drip irrigation if possible. The soil should be moist but not saturated.
Soil
Peanuts grow best in loose, well-drained, sandy loam with a slightly acidic soil with a pH range of 6.0–6.5 . Avoid poorly drained and hard clay soil. Do not plant peanuts in the same space where you have grown other legumes (beans or peas) in previous years.
Fertilizing
Some gardeners think that peanut plants don’t need any fertilizer because they fix nitrogen in the soil, but these plants can benefit from an application of bone meal or a granular fertilizer with an NPK ratio of 0-10-20 in the quantity recommended on the packaging. Add the fertilizer to the soil before the seeds are sown. Peanut plants are susceptible to fertilizer burn, so don’t over fertilize.
When the flowers start to form on the peanut plants, add gypsum to the soil at a rate of 1/2 cup per 10 feet of plants. It doesn’t burn the plants and is vital to peanut production.
Planting Instructions
In the U.S., most peanuts are grown in the South, which provides the heat, humidity, and long days these plants love. They grow best in USDA Hardiness Zones 8-11, but this summer annual can also grow in home gardens in Zones 6 and 7 if the region has plenty of warm, frost-free days.
Plant peanuts after the danger of frost has passed in spring, and the soil has warmed to at least 65°F. Sow seeds 1 to 2 inches deep and 6 to 8 inches apart in well-draining soil that is slightly acidic. Ideal row spacing for bunch types is about 24 inches apart, and 36 inches apart is best for runner types.
After the peanuts germinate and start growing, they produce yellow flowers. After the flowers are fertilized, they bend down and penetrate the soil, where they produce “pegs” that bear the peanuts. At this point, gardeners hill up the soil around the base of the plant.
Pruning
Although pruning a peanut plant isn’t required, it might increase the yield. After the plant flowers and the flowers enter the soil at the base of the plant, cut off any diseased branches or non-flowering branches.
How to Grow from Seeds
Shelling ordinary raw, uncooked peanuts gives you the seeds necessary to grow peanuts. Raw grocery peanuts can work for this, though it’s better to buy your seed peanuts from a garden center.
- Sow seeds directly outdoors after the last frost.
- Remove the seeds from their shells before sowing. But be very careful not to remove or damage the tender skin on the seeds or the seeds won’t germinate.
- Plant the seeds 1 to 2 inches deep, 4 to 6 inches apart.
- Leave 3 feet between the rows.
- Keep the soil moist to ensure germination.
- Seeds will germinate in 10 to 15 days.
- Thin the seedlings when they are about 2 inches tall, to a spacing of 8 to 12 inches.
- As the plants grow to about a foot tall, “hill” them by heaping additional soil around the base of the stem, along with light mulch for weed control. The hill accommodates the peg.
- Pegs grow from the faded flowers and push into the soil about 1 to 3 inches.
Potting and Repotting
If you’re curious and only want to grow a few peanut plants to see how they work, fill a container that is at least 18-20 inches across and 18 inches deep with loose, well-drained soil. Open a single raw peanut shell and press the two or three seeds about 2 inches into the soil, spaced evenly apart. Water the soil and put the pot outside in a place that receives at least 8 hours of direct sun daily. After the seeds germinate and the plants produce a yellow flower that drops to ground level, pull the soil into a mound around the plant base. Wait two to three months for the foliage to turn yellow. That’s the sign to pull up the plants and check the peanuts. Repotting won’t be necessary as this hot-weather annual lives only a single season.
Pests and Diseases
Peanut plants can fall prey to several common garden pests, including thrips and leafhoppers, both of which can be treated with neem oil or insecticidal soap.
Row covers can discourage moths that lay eggs resulting in leaf-eating worms and caterpillars. The caterpillars can be treated with a biological insecticide containing Bt (Bacillus thuringiensis), which is not harmful to people.
III. Uses and Benefits
- Whole peanuts
Dry-roasting peanuts is a common form of preparation. Dry peanuts can be roasted in the shell or shelled in a home oven if spread out one layer deep in a pan and baked at a temperature of 177 °C (351 °F) for 15 to 20 min (shelled) and 20 to 25 min (in shell).
Boiled peanuts are a popular snack in India, China, West Africa, and the southern United States. In the US South, boiled peanuts are often prepared in briny water and sold in streetside stands.
A distinction can be drawn between raw and green peanuts. A green peanut is a term to describe farm-fresh harvested peanuts that have not been dehydrated. They are available from grocery stores, food distributors, and farmers markets during the growing season. Raw peanuts are also uncooked but have been dried/dehydrated and must be rehydrated before boiling (usually in a bowl full of water overnight). Once rehydrated, the raw peanuts are ready to be boiled.
- Peanut oil
Peanut oil is often used in cooking because it has a mild flavor and a relatively high smoke point. Due to its high monounsaturated content, it is considered more healthful than saturated oils and is resistant to rancidity. The several types of peanut oil include aromatic roasted peanut oil, refined peanut oil, extra virgin or cold-pressed peanut oil, and peanut extract. Refined peanut oil is exempt from allergen labeling laws in the United States.
- Peanut butter
Peanut butter is a food paste or spread made from ground dry roasted peanuts. It often contains additional ingredients that modify the taste or texture, such as salt, sweeteners, or emulsifiers. Many companies have added twists on traditionally plain peanut butter by adding various flavor varieties, such as chocolate, birthday cake, and cinnamon raisin. Peanut butter is served as a spread on bread, toast or crackers, and used to make sandwiches (notably the peanut butter and jelly sandwich). It is also used in a number of confections, such as peanut-flavored granola bars or croissants and other pastries. The United States is a leading exporter of peanut butter, and itself consumes $800 million of peanut butter annually.
- Peanut flour
Peanut flour is used in gluten-free cooking.
- Peanut proteins
Peanut protein concentrates and isolates are commercially produced from defatted peanut flour using several methods. Peanut flour concentrates (about 70% protein) are produced from dehulled kernels by removing most of the oil and the water-soluble, non-protein components. Hydraulic pressing, screw pressing, solvent extraction, and pre-pressing followed by solvent extraction may be used for oil removal, after which protein isolation and purification are implemented.
- Animal feed
Peanut plant tops and crop residues can be used for hay.
The protein cake (oilcake meal) residue from oil processing is used as animal feed and soil fertilizer. Groundnut cake is a livestock feed, mostly used by cattle as protein supplements. It is one of the most important and valuable feeds for all types of livestock and one of the most active ingredients for poultry rations. Poor storage of the cake may sometimes result in its contamination by aflatoxin, a naturally occurring mycotoxin that is produced by Aspergillus flavus and Aspergillus parasiticus. The major constituents of the cake are essential amino acids such as lysine and glutamine. Other components are crude fiber, crude protein, and fat.
Some peanuts can also be fed whole to livestock, for example, those over the peanut quota in the US or those with a higher aflatoxin content than that permitted by the food regulations.
Peanut processing often requires dehulling: the hulls generated in large amounts by the peanut industries can feed livestock, particularly ruminants.
IV. Harvesting and Storage
Several signs will tell you that peanuts are ready to be harvested in late summer or early fall. The most obvious is yellowed foliage, but you should also pull a couple of pods from the ground and inspect them carefully. Ready-to-harvest pods have the typical veined surface, the seed coats are colored, and most of the pods have a darkened inside surface. When you harvest the peanuts, the soil must be dry.
- Dig or pull the entire plant from the ground and gently shake it to remove excess soil.
- Hang the plants with the peanuts attached in a dry, warm location with good air circulation.
- Leave them to cure for about one week.
- After curing, shake the soil from the pods.
- Remove the peanuts from the vines.
- Continue to air-dry the peanuts for another week or two.
Find Where to Buy the Best Peanut (Arachis hypogaea)
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