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Growing
Peanuts
The peanut
is grown as an annual crop. It can grow up to 21/2 feet
(75 centimeters)
high and from 3 to 4 feet (90 to 120 centimeters)
across. Peanut plants
range in type from bunch plants to runner plants.
Bunch plants grow
upright. Runner plants spread out on or near the
ground as they grow.
Growers group peanuts into four market types:
(1) large-seeded
Virginias; (2) smaller-seeded Virginias, called
runners; (3) Spanish;
and (4) Valencia. Both kinds of Virginias include
bunch and runner
plants. Spanish and Valencia types are bunch.
Peanut
plants bear many small, yellow, pea like flowers where the
leaves are
attached to the stems. The plants blossom continuously for
two to three
months. Flower buds open at sunrise. Fertilization takes
place during
the morning, and the flowers usually wither and die about
noon. Within a
few days, the pegs (stalk like stems of the pods) begin
to grow. They
grow slowly at first, but gradually grow more rapidly.
The pegs
grow downward and push into the soil to a depth of 1" to 3"
(2.5 to
8 centimeters). The grown pegs may be about 7"(18 centimeters)
long. The tips of the pegs contain the developing seeds. They swell
and
mature into peanut pods. Most pods contain two seeds, but some
may
contain only one or as many as five seeds.
Cultivation.
Peanut plants grow best in light, well-drained, sandy soil.
They need
much sunshine, warm temperatures, moderate rainfall, and
a frost-free
growing period of four or five months.
Farmers
prepare the soil by plowing it deeply and thoroughly. Loose
soil is
important so that the pegs can penetrate the soil easily.
Farmers plant
peanut seeds 2" to 3"(5 to 8 centimeters) deep at
intervals of 3"
to 6" (8 to 15 centimeters), and in rows 24" to 36" (60
to 90
centimeters) apart.
Farmers must
harvest peanuts at exactly the right time. If they harvest
their peanut
crops too early, many of the pods will not have ripened. If
they harvest
their crops too late, the pegs may snap, and many of the
pods will be
left in the soil. Most of the pods ripen 120 to 150 days
after planting.
At harvest
time, farmers use mechanized diggers to slice through the
tap (main)
root of each plant below soil level. The plants, with pods
attached, are
dug from the soil and turned upside down to dry in the
sun. Special
machines called peanut combines remove the pods from
the sun-dried
plants. The pods are further dried artificially in wagons.
The pods are
cleaned and graded before they are shelled for
processing.
Processing
peanuts
Most shelled
peanuts are either oil roasted or dry roasted. Oil roasting
is the more
widely used method. In this process, manufacturers blanch
the peanuts
and fry them in oil. Dry-roasted peanuts are glazed with oil
sprinkled
with salt, and roasted in large ovens.
Over 60
percent of the world's peanut production is used to produce
oil. Some
processors use a chemical solvent to dissolve oil from the
peanuts. The
oil is recovered from the solution by evaporation. In
another method,
peanuts are ground and pressed in large tube
shaped grinders. The oil is
collected, filtered, and deodorized. The
peanut meal left over after the
oil is extracted is sometimes ground
into peanut flour. In some
countries, people eat peanut meal as a
high-protein meat substitute.
Contributor: William D.
Branch, Ph.D., Prof. of Agronomy, Univ. of Georgia.
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