How Peanuts Grow: from Pegs to Pods
The peanut is unusual
because it flowers above the ground, but fruits below the ground.
Typical misconceptions of how peanuts grow place them on trees, like
nuts, or growing as a part of a root, like potatoes.
(kernels) grow into a green oval-leafed plant about 18 inches tall
which develops delicate yellow flowers around the lower portion of the
plant. When pollinated, the flowers lose their petals as the fertilized
ovary begins to enlarge. The budding ovary or "peg" grows down away
from the plant, forming a small stem, which extends to the soil. The
peanut embryo is in the tip of the peg, which penetrates the soil. The
embryo turns horizontal to the soil surface and begins to mature taking
the form of a peanut. The plant continues to grow and flower,
eventually producing some 40 or more mature pods. From planting to
harvesting, the growing cycle takes about four to five months,
depending on the type or variety. The peanut is a nitrogen-fixing
plant; its roots form modules which absorb nitrogen from the air and
provides enrichment and nutrition to the plant and soils.
How Peanuts Are Planted And Harvested
grown and treated peanut seeds from the previous year's crop are
planted about two inches deep, one every three or four inches, in rows
about three feet apart after the last frost in April and when the soil
reaches 65 to 70 degrees F. In about two weeks, the first "square" of
four leaflets will unfold above the peanut field. Thirty to forty days
after emergence the plants bloom and "pegs" form and enter the soil.
The peanut hulls and kernels develop and mature during the next 60 to
70 day period. Depending on the variety, 120 to 160 frost free days are
required for a good crop.
When the plant has matured and the
peanuts are ready to be harvested, the farmer waits until the soil is
not too wet or too dry before digging. When conditions are right, he
drives his digger up and down the green rows of peanuts plants. The
digger has long blades that run four to six inches under the ground. It
loosens the plant and cuts the tap root. Just behind the blade, a
shaker lifts the plant from the soil, gently shakes the dirt from the
peanuts, rotates the plant, and lays the plant back down in a
"windrow," -peanuts up and leaves down.
Peanuts contain 25 to 50%
moisture when first dug and must be dried to 10% or less so they can be
stored. They are generally left in the windrows to partially dry for 2
or more days in the field, before being combined.
drives his combine over the windrows. The combine lifts up the plants,
separates the peanuts from the vine, blows them into a hopper on the
top of the machine, and lays the vine back down in the field. The
peanuts are then dumped into wagons and further dried to 10% moisture
with warm air forced up through the floors of the wagons. They are then
taken to nearby peanut buying stations where they are sampled and
graded by the Federal-State Inspection Service to determine their value.
After the peanuts are purchased, they are placed in cold storage and eventually shelled or processed in the shell.