Peanuts (Arachis hypogaea) are unique legumes whose fruit develops beneath the soil, unlike true nuts. This distinctive growth habit makes cultivation a rewarding project for gardeners. Growing peanuts from seed requires specific preparation, careful planting, and attention to the plant’s unusual reproductive cycle. This guide provides the necessary steps to successfully produce a harvestable crop of these groundnuts.
Essential Pre-Planting Requirements
Peanuts require a lengthy growing season of 120 to 150 frost-free days with consistent warmth. They need a location that receives full sun, meaning a minimum of six hours of direct sunlight daily. Soil preparation is important, as peanuts thrive in a loose, well-drained, sandy loam that provides minimal resistance for developing pods.
The soil pH should be slightly acidic to neutral, ideally between 6.0 and 6.5, to maximize nutrient availability. As legumes, peanuts fix atmospheric nitrogen using Rhizobium bacteria. If peanuts have not been grown in the garden before, inoculating the seeds with a garden-specific peanut inoculant is advised to ensure this process occurs effectively.
Gardeners must source raw, unroasted seeds specifically for planting. Purchasing garden-specific seeds offers a higher guarantee of viability than grocery store peanuts. It is recommended to shell the seeds just before planting to prevent damage and encourage rapid germination.
Planting and Initial Care
Sow peanut seeds directly after the last frost when the soil temperature consistently reaches at least 65°F (18°C). Planting in cold soil slows germination and increases the risk of fungal diseases. Soaking the shelled seeds overnight in water can help accelerate germination.
Plant seeds one to two inches deep and space them about six inches apart. Rows should be spaced 24 to 36 inches apart to allow room for spreading and the later hilling process. Seedlings typically emerge within seven to 15 days.
Consistent moisture is necessary during germination and early growth, but avoid waterlogging the soil. Established seedlings require one to two inches of water per week. Maintaining consistent moisture is important when the plants begin to flower, signaling the start of underground pod development.
The Critical Pegging Stage
The peanut plant uses a unique reproductive process called geocarpy, where flowers form above ground but the fruit develops below the soil. Small, yellow, self-pollinating flowers appear on the lower branches 30 to 40 days after emergence. After fertilization, the flower petals drop, and the stalk beneath the ovary begins to elongate.
This elongated stalk, called a “peg,” grows downward to penetrate the soil. The developing peanut embryo is located at the tip of this peg, which is guided toward the earth. Once the peg pushes into the loose soil, the tip swells and develops into the characteristic peanut pod.
The success of the crop depends on the soil structure during this pegging stage. Ensure the soil around the plant base remains loose and friable so the pegs can easily penetrate. Hilling, or mounding loose soil around the plant’s center, provides more space for pods to develop. Applying mulch, such as straw, helps keep the soil surface cool and soft, assisting the pegs in their downward growth.
Harvesting and Curing the Crop
Determining the harvest time is important because peanuts do not ripen after being dug up. Peanuts are ready when the foliage begins to yellow and wilt, typically 120 to 150 days after planting. To confirm maturity, dig up a test plant and check the pods; the nuts should fill the shell, and the inner shell walls should be darkened and brownish.
When ready, carefully dig up the entire plant using a garden fork to avoid damaging the underground pods. Harvest when the soil is slightly dry to prevent pods from becoming encased in wet dirt. Once lifted, gently shake the whole plants, with the nuts still attached, to remove excess soil.
The harvested plants must undergo a mandatory curing process to reduce moisture content. Curing is essential for developing flavor and ensuring long-term storage without mold. Hang the plants in a warm, dry, and well-ventilated location, such as a garage or shed, for two to four weeks.
After this initial drying, remove the peanuts from the vines. Spread them in a thin layer to complete the curing process. Curing is complete when the shells are brittle and the nuts are fully dry.