Peanuts (Arachis hypogaea) are a legume in the Fabaceae family, grown not for a pod that hangs on the vine but for one that buries itself underground to mature. After pollination, the flower stalk, called a peg, bends downward and pushes into the soil, where the pod forms and fills out of sight. This underground habit, known as geocarpy, makes peanuts feel more like a root crop at harvest time even though botanically they're closer to beans. They're native to South America and need a long run of warm weather to size up a crop, which makes them a middling-difficulty choice for a Kentucky garden: easy enough to grow, but demanding on season length in zone 6b.
Sowing and planting
Peanuts are planted directly from raw, unroasted shelled peanuts, or from seed sold specifically for planting, since the kernels don't transplant well once they've sprouted. Wait until the soil has warmed past 65°F (18°C) and all danger of frost has passed; in zone 6b that typically means mid-to-late May. Peanuts planted into cold, wet soil germinate poorly and sit stalled, so there's little to gain from rushing them in early. Sow seeds 1.5 to 2 inches (4 to 5 cm) deep, spacing plants 12 inches (30 cm) apart in rows 24 to 30 inches (60 to 75 cm) apart to leave room for the pegs to reach soil on both sides of the row. Loose, sandy or well-drained loam suits peanuts best, since the pegs need to penetrate easily and the pods need room to expand without fighting compacted ground. Because a full 130-day peanut doesn't leave much slack against Kentucky's first fall frost, choosing an early-maturing variety matters more here than almost any other decision you'll make with this crop.
Growing on
Water regularly through germination and early growth, then pay particular attention once plants begin flowering: this is when pegs form and push into the soil, and dry conditions during flowering and pod fill cut yields more than drought at any other stage. Ease off as pods approach maturity, since wet soil late in the season can encourage pod rot. Peanuts are legumes and fix much of their own nitrogen through root nodules, so a high-nitrogen fertilizer does more harm than good, pushing leafy growth at the expense of pods. What peanuts do need is calcium in the root zone where the pods are forming, since a shortage there produces shriveled or unfilled kernels even when the plant looks healthy above ground; a light application of gypsum worked into the soil near the base of the plants at flowering time addresses this without raising soil pH.
Hill soil gently around the base of each plant once flowering begins, similar to hilling potatoes, to give the pegs loose ground to enter close to the stem. Keep the bed weeded while plants are young, since peanuts compete poorly with weeds early on; once the canopy fills in it shades out most new weed growth on its own.
Harvesting
Peanuts are ready around 130 days after planting, but the surest sign is the foliage: once a good share of the leaves have turned yellow, pull a test plant and crack open a few pods. Mature pods show dark veining on the inside of the shell and kernels with papery skins in their final color. Dig before the first hard frost, since frost damages the foliage and can affect flavor in pods still in the ground. Loosen the soil around each plant with a garden fork, then lift the whole plant by its stem; most of the pods will come up still attached to the roots.
Shake off loose soil and cure the plants before shelling: hang them upside down or spread them in a single layer in a warm, dry, airy spot out of direct sun for two to three weeks. Curing dries the pods down evenly and develops the roasted flavor peanuts are known for; shelling and storing them too soon traps moisture that encourages mold. Once cured, store shelled or unshelled peanuts somewhere cool and dry.
Problems and pests
Small tan spots on the leaves that enlarge and merge
Leaf spot, caused by Cercospora fungi, shows up as circular brown or tan lesions, often ringed with yellow, that spread and can defoliate a plant late in the season. It survives in old plant debris, so rotate peanuts and other legumes away from the same bed each year, avoid overhead watering that keeps foliage wet, and clear plant debris after harvest.
Wilting plants with a white, cottony growth at the stem base
Southern blight, a soil-borne fungus, attacks the stem right at soil level and causes sudden wilting even when the soil is moist. It thrives in hot, humid conditions and dense plantings with poor airflow. Remove and destroy affected plants promptly, avoid planting peanuts in the same spot in consecutive years, and space plants to let air move through the bed.
Pods hollow or tunneled when you dig them
Wireworms and white grubs, both soil-dwelling larvae, chew into developing pods underground, and the damage usually isn't visible until harvest. They're more common in beds recently converted from lawn. Rotate peanuts away from the same ground each year, and turn the soil in late fall to expose overwintering larvae to birds and cold.
Pods missing or shells left scattered at harvest time
Squirrels, chipmunks, and other rodents dig up ripening pods, often just as they mature, and leave empty shells behind. A layer of hardware cloth buried around the bed deters digging better than any repellent, and harvesting promptly once pods are ready limits how long they sit exposed underground.
Yellowing between the leaf veins on otherwise healthy plants
This pattern, called interveinal chlorosis, usually points to an iron deficiency brought on by heavy, poorly drained clay soil rather than a pest. Working compost into the bed before planting improves drainage and makes iron more available to the roots; it's rarely worth treating with iron supplements directly.
Varieties worth growing
- Early Spanish – A quick-maturing type bred for shorter seasons, with small, high-oil kernels; one of the more reliable choices for Kentucky's frost-free window.
- Tennessee Red Valencia – A sweet, flavorful variety with three to four kernels per pod, suited to home gardens and shorter summers.
- Georgia Green – A dependable, moderate-season variety widely grown for its consistent yields.
- Jumbo Virginia – Large kernels good for roasting, but a longer season than most Kentucky gardens can comfortably offer; worth trying only if you can start it early under cover.
- Carolina Black – An heirloom type with dark-skinned kernels and a rich, nutty flavor, grown more for novelty and taste than yield.