The peanut's scientific name is Arachis hypogaea. Arach in the U.S. are located in the South and Southwest, but home gardeners across the U.S. may be able to grow peanuts in their backyards.
As a member of the Pea family (Leguminosae or Fabaceae), backyard gardeners in even northern zones can grow these plants.is refers to a group of plants with pods that ripen underground, and hypogaea means "under the earth" because the capsules mature underground.
Domesticating Peanut Plants
The ancient Incas domesticated peanuts in Peru and Brazil long before Europeans landed upon their shores. Archaeologists found peanut remains in Peruvian sites dating back 7,600 years ago. Spanish conquistadors brought the nut home with them, and then European traders helped spread peanuts to Africa and Asia. The peanut came back to the New World in the 1700s, but it wasn't until after the Civil War that demand for peanuts grew in the U.S. Today, peanuts are grown worldwide with China and India as the highest producers.
There are four main varieties of peanuts that are grown: Virginia, Valencia, Spanish and Runner. Hundreds of cultivars from these groups are grown depending upon the products the peanuts are being grown for. The large Virginia peanuts are grown for the unshelled market and are often roasted in the shell. Valencias have bright red skins and are the sweetest peanut of the four; they are also grown for the "in shell" market. Spanish peanuts are small and often included in mixed-nut snacks, peanut candy, salted nuts and peanut butter. Uniform in size, Runner peanuts are grown mostly for peanut butter.
In addition, there are two main types of plants: bushes and runners. Bushes have upright growth, while the runners grow along the soil surface.
Although you can use unroasted, unshelled peanuts for planting, most gardeners purchase peanut seed from various seed companies. They are shipped in their protective shells to prevent damage to the nuts.
Warm Growing Conditions
Peanuts do best in warm climates with a long growing season and plenty of sun. Soil temperature for germination needs to be between 65-70°F (18-21°C), and seeds should germinate in 10-14 days. Gardeners may plant the entire shell, then thin plants, rather than planting individual seeds and risking damage to the seed. In the South, seeds may be planted 3-5 inches deep and spaced about 8 inches apart. In more Northern climates, the planting depth is 1 1/2-2 inches deep, and with rows spaced 2-3 feet apart.
Most peanuts grow in well-drained, moderately fertile soil. The key to growing peanuts is to hill organic matter or loamy soil around the plants so that the plant's "pegs" can easily penetrate the soil and the nuts mature underground. Be careful not to overwater plants.
The plants need a fairly long frost-free season - most varieties mature between 120-150 days. Obviously, peanuts do well in the South and Southwest, but some colder climate gardeners rise to the challenge of raising plants in hardiness zones 1-4. In these areas, peanuts would have to be grown in preheated raised beds, greenhouses, under row covers or in containers where they can be brought in during summer cold spells. Peanuts may be started indoors then transplanted outside after the annual average frost free date.
As the plant flowers, gardeners should hand-weed around the base of the plants to minimize damage to the flowers and to loosen the soil around the base. When the petals fall off, the plant's peduncle (the stalk below the ovaries) or "peg", begins to elongate and bend down towards the soil. The peg penetrates the soil and grows underground where the ovaries develop and form the pod.
When the leaves turn yellow and start to drop, this is the time to harvest the plants. Use a pitchfork to gently dig up the entire plant, then remove excess soil from the roots and cure the plants in the sun or a dry location. When the pods are dry (this might take several days or up to 2 weeks depending upon temperatures), remove the seedpods from the plants and continue to cure them in the sun or a dry location for several more weeks until completely dry. The unshelled nuts can be stored for several months in cool storage or eaten! Save some of the largest capsules for next year's crop.
Under ideal conditions, each plant should produce between 50 and 100 capsules. So if you are a fan of peanuts, they are worth a try growing in the backyard garden.