Peanuts are a beloved ingredient that has grown in popularity over the years and has slowly worked its way into almost everything. From a raw snack and being mixed with chocolate and other sweets to being part of a multitude of savory dishes and making delicious butter, there’s nothing this little thing can’t do.
What many might not know is that peanuts are not nuts. In fact, they’re not even fruits but versatile legumes, like lentils or beans. These unusual plants have special growing habits and interesting biology.
Today, we’ll let you in on everything peanut, from how do peanuts grow and are harvested to how you can add this crop to your garden.
Peanuts are a fascinating agricultural crop. When many people think of peanuts, they imagine the delicious roasted peanut snacks or rich peanut butter. But few people realize that peanuts are not actually a nut at all! Peanuts are a legume, closely related to beans and peas. And they have a very unique growing process that results in the peanut pods forming underground. So what does a peanut plant actually look like above ground? In this article, we’ll explore the full peanut plant lifecycle and provide a visual guide to the growth stages of this unusual crop.
Peanut Plants Above Ground
Let’s start with the visible portion of the peanut plant that grows above ground. A peanut plant has a bushy growth habit, with multiple branches extending along the ground away from the central stem The plants reach an average height of about 1-2 feet tall and spread out around 3 feet wide.
The leaves of the peanut plant are oval-shaped, usually about 4 inches long. The leaves are arranged in pairs along the stem, and are typically a light green color. Young peanut plants just emerging from the soil will have smooth, hairless stems and leaves. As the plants mature over 4-6 weeks, they develop fine hairs on the stems and underside of leaves.
After growing for about 4-6 weeks, small yellow flowers start to bloom on the peanut plant. The flowers emerge from the leaf axils, which is where the leaf stalks join the stem. The peanut flowers have a 5-petaled shape, similar to flowers in the pea family. Once pollinated by bees or other insects, the peanut flowers drop off the plant.
Pegs and Pods Form Underground
Here’s where it gets really fascinating! After the peanut flowers are pollinated, the fertilized ovary starts to elongate into a structure called a “peg.” The peg grows down toward the ground, sort of like a vine. Once it reaches the soil surface, it extends into the ground. This is a key stage in peanut development, as the tip of the peg will form the peanut fruit pod.
The peanut pod develops underground, attached to the end of the peg. Inside the pod the edible peanut seeds will form and mature. A single plant can produce 40 or more pods. The pods are usually 1-2 inches long and may contain 2-4 peanut seeds.
As the pods enlarge underground the interior lining of the pods changes color from white to yellow orange, brown and finally black. This color change indicates the pod and peanut seeds inside are reaching full maturity.
Digging Up the Entire Peanut Plant
So when do we actually see the peanuts? The pods and seeds remain hidden underground until harvest time. Peanut plants are ready for harvest about 120-160 days after planting. Harvesting peanuts requires digging up the entire plant to expose the peanut pods so they can be collected.
The best time to harvest is just after the peanut plant foliage starts to yellow and wilt. The pods need to be mature, but the soil can’t be too dry or pods may detach during digging.
Commercial peanut harvesting uses specialized equipment to invert and shake plants to dislodge the pods. But garden-scale growing can be dug up by hand. After digging, the plants are laid upside down for a few days to dry and loosen the pods for removal. Then the peanuts are cured indoors for 2-3 weeks at warm temperatures to complete the drying process.
The Life Cycle of Peanuts: From Flower to Food
To summarize the unique peanut plant lifecycle:
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The seedling emerges above ground about 1-2 weeks after planting.
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The plant grows leaves, stems, and branches over 4-6 weeks.
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Yellow flowers bloom on above ground stems.
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Fertilized flowers form pegs that extend into the soil.
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Pegs develop into peanut pods underground.
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Pods and seeds mature for 120-160 days.
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The entire plant is dug up to reveal the mature peanuts.
So while the most delicious part of the peanut plant is concealed underground as it develops, the above ground foliage and flowers are still interesting to observe as the hidden peanuts grow. Getting to dig up those mature peanut pods at harvest is like discovering buried treasure!
Frequently Asked Questions
Do peanuts grow on vines above ground or underground?
Peanuts grow on bushy above ground plants, not vining plants. But the edible pods and seeds develop underground once the fertilized flowers form pegs that grow down into the soil.
Is a peanut plant a tree, vine, or bush?
Peanuts plants have a bushy growth habit. Unlike tree nuts, peanuts are not grown on trees. And they do not vine or climb like pole beans.
How long does it take to grow peanuts?
Peanut plants need a long warm growing season of at least 120-160 days of frost-free weather to fully mature.
What does the foliage look like?
The peanut plant has oval shaped leaves. Young plants have smooth stems and leaves, while mature plants develop fine hairs. The plants grow 1-2 feet tall and spread about 3 feet wide.
When do the flowers bloom?
Small yellow, pea-like flowers bloom on the above ground peanut plants about 4-6 weeks after planting. These flowers must be pollinated to produce the pegs and underground pods.
How are peanuts harvested?
The entire peanut plant is dug up to expose the mature pods for picking. Commercial production uses specialized equipment, while home gardeners can dig plants by hand.
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What Is a Peanut Plant?
Although many think peanuts will grow similarly to other “nuts”, on trees, peanuts actually grow on a bush-like plant that usually doesn’t exceed 18 inches (46 cm), similar to other legumes.
This plant develops normally above ground, with its foliage and flowers, while underground, the roots, pegs, and pods grow. These pods are where the seeds, or peanuts, develop and are an unusual biological occurrence.
How Do Peanuts Grow — Life Cycle
You’ve heard about peanuts’ “strange biology”, but what does this actually mean? The stages of the growing cycle of peanuts are not far from the majority of legumes, they just happen differently. Here’s how peanuts grow:
Peanut seeds are planted by mid to late spring when temperatures are around 65-70 ºF (18-21 ºC).
Around 10 days after sowing, seedlings will begin to erupt from the soil. They will proceed to mature and grow up to 18 inches (46 cm) tall.
When around 40 days have passed, yellow flowers will begin to bloom close to the ground, around the lower portion of the peanut plant. They’ll then self-pollinate and fall off.
From the fecund flowers, stem-like structures known as pegs will grow toward the ground, perforate the soil and begin to develop into peanut pods. Each plant can develop around 40 or more pods.
Harvesting is usually done in fall and consists of digging up the plant to expose the ripe pods to open air for them to dry out and be ready to store.
