Growing peanuts By Shauna Dobbie
Did you know? Peanuts are legumes, not nuts!
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ave you ever thought of growing peanuts? It’s not crazy if you live in Southern Ontario, where days are hot and the summer extends long enough. Nova Scotia is another spot where peanut growing has been successful. It’s more of a chore if you live on the West Coast, where the growing season is long but the daytime temperatures are more temperate. On the prairies, the shorter growing season is sure to be a challenge. Let’s look at how you can try to overcome your environmental challenges and grow some peanuts at home. How peanuts work First off, peanuts aren’t nuts. They’re legumes. Peanuts aren’t like any other plant you’ve likely grown in that they are geocarpic. This means that they flower above ground but produce their seeds underground.
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The plant produces bright yellow flowers that look like other legume flowers of beans or peas. Once that flower is pollinated—and it pollinates itself, not requiring wind or insects—a structure at the base of the flower grows longer, down toward the soil. This structure, called a peg, contains the pollinated ovary at the tip, which develops the peanut pod underground. That’s right: a peanut pod is like a bean pod except that it grows underground. This process is called geocarpy. A few plants reproduce like this, but the peanut is the best known. Peanuts originated in South America, probably in Argentina and Bolivia. When Linnaeus, the great namer of plants considered them, he gave them the Latin name Arachis hypogaea. The specific epithet hypogaea translates as “below the earth”, owing to peanuts developing their Issue 3
seeds in the ground. The genus name, which sounds like something to do with spiders (arachnids) is, in fact, the name of a plant called chickling vetch. Heat Peanuts require at least 95 days to reach maturity and most varieties require 120 or more. There are more than 95 frost-free days across the southern prairies, where most places enjoy a growing season from just before June through at least the beginning of September. But peanuts need 3,000 corn heat units (CHU) to mature. If they get less heat, they won’t mature to their full potential. You will get a reduced harvest. What is CHU? It’s a complex number based on maximum and minimum temperatures that accumulates from April 1 to October 31. A minimum of 3,000 CHU is reached in a few places in Canada, in 2021 • 27
