Arachis hypogaea.

The peanut does something no other garden plant does, and it's worth knowing before you sow it. It flowers normally, in small yellow flowers carried in the leaf axils. Then, once the flower is fertilized, the stalk that carried it lengthens, bends toward the ground, and literally drives the ovary into the soil. It's there, underground, in darkness, that the pod forms and ripens. Botanists call this geocarpy, and it's where the species' Latin name comes from — hypogaea, “under the earth.” Children who dig up their first peanut plant remember it for a long time.

Botanically it isn't a nut but a legume, a cousin of the pea and the bean, domesticated in South America, in the region of present-day Bolivia, about 7,500 years ago. The Valencia type is one of the four great commercial peanut types, and the sweetest of them all: thin-shelled pods containing three or four red-skinned seeds, rather than the two seeds of the common types. It's the type used for natural peanut butter, precisely because it's sweet enough to need nothing added, and it's also the type used for boiled peanuts in the American South. Dry-roasted in the oven at 160 °C for twenty minutes, straight out of the garden, they bear no resemblance to store-bought.

Grower's tip: 120 days is long for Québec, and the peanut wants heat from start to finish. Start indoors 4 weeks before transplanting, in deep pots, and put it in the garden only when the soil is genuinely warm. Two moves change everything: a black plastic mulch, which warms the soil by several degrees all season, and sandy, loose soil, because the diving stalk has to be able to penetrate easily — a hard crust and the peanut sets no pods. Hill up lightly at the base at flowering to give it loose soil to drive into. At harvest, pull the whole plant before the first frost and let it dry two to three weeks in an airy place, pods attached: it's that drying that develops the flavour.

• Open-pollinated. Annual, self-pollinating. A legume: fixes nitrogen and leaves the soil enriched for the next crop.
• Grows to ~45 cm (18") in ~120 days.
• Exposure: full sun, the warmest spot in the garden.
• Sandy, loose, well-drained, stone-free soil. Black plastic mulch strongly recommended in Québec. Space plants 25 to 30 cm apart.
• Start indoors 4 weeks before transplanting, in deep pots. Transplant once the soil is at least 18 °C.
• Pull the whole plant before frost and dry 2 to 3 weeks before shelling.