All About Peanuts

Reviewed by Darlene Cowart, PhD

Is a Peanut a Nut?

Botanically, peanuts are classified as legumes; however, for culinary, research and nutritional purposes, peanuts are considered a nut. Peanuts grow underground, as opposed to nuts like walnuts, almonds, etc. that grow on trees.

Is a Peanut a Legume?

Peanuts, along with beans and peas, belong to the single plant family, Leguminosae. Legumes are edible seeds enclosed in pods. As a group, they provide the best source of concentrated protein in the plant kingdom. While their physical structure and nutritional benefits more closely resemble that of other legumes, peanuts’ use in diets and cuisines more closely resembles that of nuts.

How Do Peanuts Grow?

Peanut seeds (kernels) grow into green leafed plants about 18 inches tall. Unlike most plants, the peanut plant flowers above the ground, but fruits below the ground. Yellow flowers emerge about 40 days after planting. When the flowers pollinate themselves, the petals fall off as the peanut ovary begins to form. This budding ovary is called a “peg”. The budding ovary or ‘peg’ grows down away from the plant forming a small stem which extends to the soil. The peanut embryo turns horizontal to the soil surface and begins to mature, taking the form of a peanut. Peanut plants are indeterminate in fruiting. This means that they continue to flower, peg, and produce peanuts over an extended period of time, as environmental conditions allow. From planting to harvesting, the growing cycle takes four to five months, depending on the type or variety.