Peanut plants (Arachis hypogaea) are unique because their edible pods develop beneath the soil. This guide will help home gardeners understand and successfully grow this distinctive crop.
Understanding Peanuts
Peanuts are legumes, not true nuts, belonging to the same plant family as beans and peas. These annual plants complete their life cycle in a single growing season. Native to tropical South America, peanut plants are low-growing and bushy, typically reaching 1 to 2 feet tall with a spread of up to 3 feet.
Peanuts have a distinctive flowering and fruiting process. Small, yellow, self-pollinating flowers appear above ground. After pollination, a specialized structure called a “peg” or “gynophore” emerges from the flower’s base. This peg elongates, growing downward into the soil, where the peanut pods then develop and mature underground.
Cultivating Peanuts
Site and Soil Preparation
Peanuts thrive in locations that receive ample sunlight, ideally eight or more hours of direct sun daily. The soil plays a significant role in peanut development because the pods form underground. Loose, well-draining, sandy loam soil is optimal, allowing the pegs to penetrate easily and the pods to expand.
A slightly acidic to neutral soil pH, typically between 6.0 and 6.5, is suitable for peanut growth. Conduct a soil test before planting to determine existing nutrient levels and pH. If needed, incorporate organic matter such as compost to improve soil structure and fertility, ensuring good drainage and aeration.
Planting Techniques
Planting should occur in spring after the last frost, when soil temperatures consistently reach 65° to 70°F (18° to 21°C). Plant raw, shelled peanuts directly into the garden. If using in-shell peanuts, crack them open just before planting, leaving the thin red seed coat intact.
Sow seeds approximately 1.5 to 2 inches deep. Space them 4 to 6 inches apart within the row, with rows separated by about 2 to 3 feet. After planting, water thoroughly to ensure consistent moisture for germination, which usually occurs within 10 to 15 days.
Ongoing Care
Consistent moisture is necessary for peanut plants, especially during key growth stages. They require about 1 inch of water per week, from rainfall or irrigation. Watering is particularly important from flowering until pegs have fully developed and burrowed into the soil, typically 60 to 110 days after planting. Reduce watering 1 to 2 weeks before harvest.
As legumes, peanuts fix their own nitrogen in the soil through symbiotic bacteria in their roots, so they need minimal nitrogen fertilizer. Calcium is important for proper pod development and can be supplied through amendments like gypsum or bone meal if soil tests indicate a deficiency.
Maintaining a weed-free area around peanut plants is important, but caution is needed. Disturbing the soil too vigorously can damage sensitive pegs as they attempt to penetrate the ground. Some gardeners “hill” plants by mounding loose soil around the base once they are 6 to 12 inches tall, which can help emerging pegs reach the soil more easily.
Harvesting and Curing Peanuts
Peanuts are typically ready for harvest in late summer to early fall, usually 120 to 160 days after planting, depending on the variety. A key indicator that peanuts are ready is when the foliage begins to yellow and wither. Harvest before the first hard frost.
To harvest, carefully loosen the soil around the plants with a shovel or garden fork. Gently pull up the entire plant, shaking off any excess soil from the roots and attached pods. Most peanuts should remain attached to the plant.
After harvesting, peanuts require a curing process to dry them properly for storage and flavor development. Leave the pods attached to the plants and hang the entire plants in a warm, dry, well-ventilated area, such as a garage or shed, out of direct sunlight. This initial drying phase can take one to two weeks.
Once the plants are mostly dry, remove the pods and spread them in a single layer on screens or newspaper in a cool, dry place for an additional two to three weeks until they are fully cured. Cured peanuts should have a moisture content of 8 to 10 percent, indicated by kernels that rattle when shaken.
Common Peanut Pests and Diseases
Home-grown peanuts can encounter common pests and diseases. Insects such as aphids, thrips, armyworms, and leafhoppers may feed on foliage. Burrower bugs can also affect underground pods.
Fungal diseases like early leaf spot, stem rot (Southern blight), Botrytis blight, and charcoal rot can affect peanut plants, particularly in warm, humid conditions. These diseases can cause leaf discoloration, wilting, or stem lesions.
To minimize issues, choose resistant varieties and ensure good air circulation around plants. Practices such as crop rotation, proper watering, and maintaining overall plant health can help prevent many problems. Encouraging natural predators can also help manage pest populations.