Peanuts: a curious crop

The nut that’s not a nut! Botanically speaking peanuts (Arachis hypogaea) are actually a legume and in the Fabaceae family, the same as peas and beans. They originated in the tropical and subtropical regions in South America, although they can be grown in cooler climates with a little bit of extra care.

Peanuts are also known as groundnuts, and while the nut is harvested from under the ground, it’s not attached to the roots. Once the yellow flower is pollinated, the stalk (called a ‘peg’) bends over and pierces the soil, forming the peanut pod underground.

Who knew peanuts could be so fascinating?

Growing

Peanuts need a long, warm growing season of four to five months above 20°C, so the best time to plant is spring, after any frost or cold snaps. In cooler climates wait until late October to November or start earlier in pots indoors and move them outside once the weather has warmed.

In subtropical climates, September onwards is perfect. In the tropics, peanuts can be grown all year round, but during the wet, there is an increased possibility of rotting crops.

Also, although they love the heat, sustained temperatures above 35°C may decrease yield. This means late February to March, as soon as the wet season has finished, is the ideal time to sow.

Like other Fabaceae, peanuts grow best from seed (that’s the ‘nut’ removed from inside the peanut shell), although seedlings are sometimes available. When sowing from seed, it is good practice to inoculate your peanuts as peanuts use bradyrhizobium bacteria to help fix nitrogen. This is where the bacteria converts atmospheric nitrogen into a form the peanut roots can use. You don’t have to inoculate but doing so will help produce better yields. The inoculant, called ‘Type P’ is often available for purchase with your peanut seeds. Toss the seeds in the inoculant with a tiny bit of water (just enough to make it stick) right before sowing.

Plant seeds 3–5cm deep, and 15–30cm apart, in loose, well-drained soil in full sun. They should germinate in 1–2 weeks if conditions are right.

Peanuts also grow well in large pots (wide enough for the flowers to be able to bend over and touch the soil). Pots are a great alternative if your soil is compacted or heavy clay, or if you are trying to grow them in cooler climates.

Pick up Issue 169 of ABC Organic Gardener in stores now to read the rest of this story on growing peanuts, or subscribe at mymagazines.com.au to get every issue delivered straight to your door.