I started my journey growing peanuts when something emerged from a planting container that I hadn’t planted. And it was unmistakably a peanut.
The only thing I could figure was that one of my local scrub jays had ‘planted’ it for later consumption. At the time, I had no bandwidth for growing peanuts. So I dug it out to take a closer look at the root system. [Now I let them grow!]
Nuts that are not nuts
Peanuts, also known as goobers, or groundnuts, are legumes. This means that they are able to ‘fix’ atmospheric nitrogen into a form they can use as food, with a little help from certain bacteria that live on or in their roots. The botanic name, Arachis hypogaea, describes a legume that produces its seeds “under the earth”, in a behavior called geocarpy. Geocarpy is rare in the plant world. It is a means of reproduction in which pollinated flowers are transformed into specialized stems, called pegs. Pegs are budding ovaries that bend downward and push their way into the soil. Seeds are produced along these pegs. Unlike other plants, which produce seeds above ground for easy dispersal, the peanuts we eat are the underground seeds of the peanut plant. And they are not nuts at all.
Parts of a peanut
If you look closely, it is easy to see how peanuts are related to peas and beans. They have very similar seed structures. Each delicious peanut has five parts:
Peanut plants come in two forms: runners and bush. Bush varieties are 18 to 22 inches tall, while runners can spread out 28 to 31 inches. Peanuts are believed to be a human construct, through artificial selection between two wild varieties. This occurred in Argentina or Bolivia, nearly 8,000 years ago. Selective breeding of this first peanut has resulted in six major and two minor landraces. A landrace is a regional, domesticated variety. These groups are:
Until the 1930s, peanuts were used predominantly as a livestock feed. That was when the USDA actively promoted peanuts as a commercial crop for human consumption.
How to grow peanuts
While it’s true that peanuts prefer the sandy loam of the southeastern U.S., peanuts can be grown in raised beds and large containers that are filled with a lightweight potting soil. You can start peanuts in a tray filled with potting soil. Make one inch deep holes by hand or with a dibble, and drop one shelled peanut into each hole, cover with soil, and water well.
In commercial peanut fields, as peanut plants begin to yellow, machinery is used to dig plants out of the ground, give them a good shake, and then flip them over and leave them on the soil surface for a few days to dry. In the home garden, you will harvest your peanuts by simply pulling the plants out of the ground, giving them a good shake to get rid of any clinging soil, and leave them, upside-down, to dry for a few days. [You may want to do your peanut drying in the garage, to protect your harvest against marauding birds and squirrels.] Next, peanuts are threshed, or removed from their stems. You may be surprised to learn just how important the drying aspect of peanut harvesting is - peanuts stored with too much moisture can become infected with a fungus (Aspergillus flavus) that produces toxic substances that can be carcinogenic. Be sure to dry your peanuts thoroughly!
You can grow a surprising amount of food in your own yard. Ask me how!