Grow peanuts in a location with at least eight hours of direct sunlight per day and loose, rich, well-drained soil. If your soil is compacted or composed of clay, add organic material such as compost to break it up. Like root crops such as carrots, peanut plants need to have spaces between soil particles where their pegs or peduncles -- the peanut seedpods -- can grow.
Northern gardeners should start peanut seeds indoors using peat or biodegradable pots that can be placed directly into the garden when the soil temperature reaches 65 degrees F.
Sow peanut seeds directly into the ground when the soil is warm. In well-drained soils, plant 2 to 3 inches deep. In clay soils, plant 1-1/2 to 2 inches deep. Seeds should be spaced 6 to 8 inches apart, then thinned to allow 18 inches between plants. To save space, plant in double rows, staggering seeds 18 inches apart.
Plants produce a small yellow flower after 30 to 40 days. Each flower produces a long pointed peg that pushes into the soil to form a peanut. When the plants are about a foot tall, mound soil around the base of the plant to allow more pegs to set. Because the plants keep setting flowers, the pegs mature at different times.
Proper watering is the key to successful peanut growing. Keep seeds and young plants moist after planting until germination. From that time until flowers set, plants need about 1 inch of rain or water each week. About 50 to 100 days after planting, keep the soil consistently moist to allow pegs to develop.
Because peanuts are shallow-rooted, hand-weed around the plants. Once pegs begin to develop, place a 1- to 2-inch layer of mulch around the plants to maintain moisture and reduce weeds.
Stop watering about two weeks before harvesting peanuts. Avoid overhead watering, which can damage the leaves.
Start with seeds from a reputable seed distributor so you know the characteristics of the variety you grow. The seeds -- the peanuts -- arrive still tucked in their shells. It's best to open and shell them for planting, although it's not necessary. Don't shuck off the papery outer layer on the seeds; that is needed for germination.
There are four major types of peanuts: Valencia, Spanish, Virginia, and runner. The seeds come in a variety of colors, including red, black, white, and variegated.
Valencia peanuts take the shortest amount of time to mature, growing three to six red seeds per pod used for roasting in the shell or for boiling. Spanish types have high oil content. Virginia peanuts, which grow the largest seeds, are sometimes called ballpark peanuts and are often used for roasting. Runner peanuts are uniform in size, with two seeds per pod.
Each peanut plant produces 30 to 50 peanuts.
Count the number of days since you planted the peanuts, checking sample pegs a week or two before the amount of time advised for that variety. It's easiest to dig when the soil is lightly moist but not wet.
When the foliage begins to turn yellow, carefully loosen the soil around the base of each plant with a spading fork or a shovel. Hand-pull or lift the plant by the base, bringing the peanuts up with the roots. Shake off excess soil. Allow the entire plant to dry, with the peanuts on it, for about a week. Leave the plant outside in the sun if no rain is forecast, or hang it in a warm, dry location, taking care not to place the pods within easy reach of rodents.
After the first round of drying, cut the peanut pods from the plant and spread them out in a single layer in a cool, dry area to cure for another two to three weeks. Check periodically to be sure no mold is growing. If you find mold, do not eat the peanuts; they may be growing a toxic fungus.
After the second round of drying, the peanuts can be roasted or stored in a mesh bag for several months in their shells in a cool, dry place.
It's a little more difficult to grow peanuts in containers because pots restrict the amount of space the underground parts of the plant can reach. Choose a pot that's at least 20 inches across and 18 inches deep per plant. Be sure your container has drainage holes, and use a potting mix; garden soil is too dense. Place the pot in full sun, and keep it well-watered but not waterlogged.
Peanuts are not nuts at all. The plants are legumes, related to peas and beans. The seeds are the peanut pods that grow underground instead of on trees like tree nuts such as walnuts and pecans.
After harvesting, peanuts can be ground into peanut butter, roasted in their shells, or boiled for a traditional Southern snack. They are nutritious ingredients in many baked and cooked foods.