The peanut (Arachis hypogaea) is an annual herbaceous plant cultivated for its edible seeds, which develop inside pods beneath the soil. Despite its common name, the peanut is classified as a legume, placing it in the botanical family Fabaceae alongside peas and beans. This classification means the plant hosts nitrogen-fixing bacteria in its root nodules, allowing it to naturally enrich the surrounding soil. Successful cultivation requires a long period of warmth and specific soil conditions to complete its unique life cycle.
Seed Selection and Proper Timing
Selecting the correct planting material is the first step toward a successful harvest. The seeds should be raw, shelled, and untreated. While raw, unroasted grocery store peanuts may sometimes germinate, specialized garden seeds offer better quality and reliability. The seeds must be carefully removed from their shells right before planting to prevent damage to the delicate kernel.
Peanuts require a long, warm growing season, typically needing between 120 and 150 frost-free days to reach full maturity. Soil temperature is the most important factor in timing. Seeds should only be planted after the last expected frost when the soil consistently reaches a minimum of 65°F, with 65°F to 70°F being ideal for germination. Planting into cold soil slows germination and increases the risk of seedling diseases.
Preparing the Soil and Planting
Peanuts grow best in a loose, well-drained, sandy loam soil, which is necessary for the developing pods to push through the ground. Heavy clay soil should be avoided, as it can hinder the underground development process. The ideal soil environment is slightly acidic to neutral, with a preferred pH range of 6.0 to 6.5.
The planting location should receive full sun for at least eight hours daily to support the plant’s growth cycle. Seeds should be sown approximately 1 to 2 inches deep into the prepared soil. Proper spacing is necessary to allow room for the underground pods to form, requiring seeds to be spaced about 6 to 12 inches apart within rows.
Essential Care and the Pegging Process
Consistent moisture is necessary for the peanut plant, especially during the initial germination phase and the later stages of pod development. Plants require about one inch of water per week. Watering is particularly important between 60 and 110 days after planting, when the pods are actively filling. Weeding is also important, as peanuts are sensitive to competition, and deep cultivation should be avoided to prevent disturbing the subterranean fruit.
The growth process is unique because the plant flowers above ground but fruits below it, a phenomenon known as geocarpy. Yellow flowers appear on the plant about 40 days after planting. Once they are self-pollinated, their petals fall off, and the fertilized ovary at the base of the flower begins to elongate, forming a structure called a “peg.”
This peg grows downward, pushing through the soil until the tip, which contains the embryo, turns horizontal and begins to mature into a peanut pod. To support this process, gardeners can gently “hill” the soil around the base of the plant once the flowers appear. Hilling involves mounding loose soil around the plant stem, which makes it easier for the pegs to penetrate the ground and encourages greater pod production.
Harvesting and Curing Peanuts
Peanuts are generally ready for harvest between 120 and 150 days after planting, depending on the variety and local climate. A clear sign of maturity is when the foliage begins to yellow and wither, indicating the plant is diverting energy to the developing pods. Before harvesting the entire crop, dig up a single plant to check if the pods are fully developed and the interior seed coats are colored.
Harvesting is done by carefully digging up the entire plant, using a garden fork to loosen the soil and avoid separating the pods from the roots. The whole plants are then gently shaken to remove excess soil. The next step is curing, which is the process of drying the high-moisture peanuts to enhance their flavor and ensure long-term storage.
The harvested plants, with the pods still attached, should be placed in a dry, dark, and well-ventilated area, such as a garage or shed. They should be hung or laid out on screens. This initial curing period typically lasts for two to three weeks, reducing the moisture content from up to 50 percent down to approximately 10 percent. After this, the pods can be removed from the stems and allowed to dry for several more weeks before they are ready for consumption or storage.