How peanuts are grown and harvested
A machine slices the taproot, flips the plant upside down and leaves the pods to dry in the open air for days.
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The short version
Peanuts flower above ground, then push their pods into light, sandy soil on stalks called pegs. At harvest a digger-inverter cuts the taproot below the pods, shakes off the dirt and flips the plants into a fluffy windrow. Two or three days later a combine threshes the pods from the vines and blows them into a basket.
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Plant in sandy loam
The crop wants light, sandy loam and warm weather all season, and harvest usually comes 90 to 150 days after planting, depending on type. Bacteria in root nodules fix nitrogen, so the plants gain little from nitrogen fertilizer and leave the soil better for the next crop.
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Peg into the soil
After fertilization a thread-like stalk called a peg lengthens and grows into the ground. The pod develops underground, a habit called geocarpy. Pods measure 3 to 7 centimeters.
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Judge the digging date
Flowers keep opening while pods fill, so a field never ripens all at once. Dig too early and many pods are unripe. Dig too late and they snap off and stay in the soil. Growers lean on the hull-scrape method to judge maturity.
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Cut, shake and invert
A horizontal blade clips the taproot just below the pods, and its slight pitch lifts the plant onto a conveyor of vibrating bars that knocks the soil loose. Wheels and rods then flip the plants into a well-aerated windrow with very few pods on the ground.
3.5 to 5 mph digging speed
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Thresh from the windrow
Combining starts when the windrow has dried to 18 to 24 percent moisture. Cylinders pull pods off the vines, sieves and an air blast take out the trash, and stemmer saws cut off the stems. An air stream lifts the pods into an overhead basket, which empties into a drying wagon.
18 to 24 percent moisture
Worth repeating
- Peanut plants are 30 to 50 centimeters tall and their leaves close at night.
- Peanuts are not true nuts but legumes, in the same family as peas.
- American growers sort the crop into four market classes: Spanish, Runner, Virginia and Valencia.
Where it comes from
2023, share of the 54 million tonnes of groundnuts, excluding shelled, produced worldwide.
Where it goes next
Peanuts feeds 1 line directly.
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Sources
Cite this page: "How peanuts are grown and harvested." Assembly Line, 2026-11-03. https://assemblyline.org/make/peanuts