Peanut

Peanuts are warm-season annuals grown mainly for their edible seeds. The plant flowers above ground, but the pods form underground after a peg grows into the soil. Pods typically ripen 120 to 150 days after planting, so the plant needs a long, warm season. Plants are not frost-hardy.

Start seeds indoors 6 to 8 weeks before the last frost, or sow directly outdoors once the soil has warmed to 60 to 70 °F (16 to 21 °C). Sow outdoors after the danger of frost is past. Some pages say peanuts are grown from seed rather than transplants, so indoor starts are an awkward case. Plant seeds 2 to 3 inches (5 to 8 cm) deep in light, sandy soil, or 1½ to 2 inches (4 to 5 cm) deep in clay. Germination is best between 68 and 95 °F (20 to 35 °C), and seeds usually come up in 10 to 15 days. Space plants 6 to 9 inches (15 to 23 cm) apart in the row, with rows about 3 feet (91 cm) apart. Peanuts can be planted in the shell or with the shell removed, but keep the red seed coat intact if you remove it. In the UK, growing outdoors is generally not suited to producing peanuts because they need a long growing season; growing under glass in full sun in light, free-draining compost is suggested.

Keep the soil moist after planting so the seeds come up evenly. Water matters most from 60 to 110 days after planting, when the pegs enter the soil and pods begin to develop. Avoid wetting the leaves when you water, and stop watering 10 days to two weeks before harvest. Peanuts prefer a soil pH between 5.8 and 6.2, so test your soil first. Mound soil up around the plants when they reach about a foot tall, and spread 2 to 3 inches of mulch to control weeds.

Diseases listed include leaf spots, southern stem rot, Sclerotinia blight, Cylindrocladium black rot and spotted wilt. Leaf spot causes brown to black spots on the leaves, and keeping leaves dry when you water helps reduce it. Mice and other ground animals may feed on developing seeds underground, and squirrels, mice and chipmunks are named as pests in one article.

Pods typically ripen 120 to 150 days after planting, and one factsheet gives 130 to 150 days for roasting types. Dig the plants in fall when the leaves turn yellow or after the first frost. Check a few pods first; ready pods have colored seed coats and mostly darkened insides.

Let the dug plants dry in the sun for about a week, then remove the pods and cure them in a cool, dry place. Discard unhealthy-looking nuts and store the dried peanuts at 35 to 40 °F (2 to 4 °C) and 50 to 60 percent humidity. Roasted nuts keep about 3 to 4 weeks at room temperature, or 6 to 12 months refrigerated.

Peanut seeds contain proteins that can cause serious allergic reactions in some people, so people with peanut allergies should avoid exposure to the seeds. One profile lists the seeds as not edible for people and pets and advises wearing gloves when handling them; other pages describe the seeds as the edible part, so the pages disagree on whether the seeds can be eaten.