Precision Seeding for
Revised 7/94 -- Author
Reviewed 8/97 HIL-36
D. C. Sanders
Extension Horticultural Specialist
Department of Horticultural Science
North Carolina Cooperative Extension Service
North Carolina State University
Precision seeding is defined as the placing of desired numbers of
seeds at a precise depth and spacing. Precision seeding has many
advantages for the vegetable grower over conventional dribble (Planet
Jr.) or multiseed drop-plate seeding systems (most corn planters).
However, the seeding accuracy is not a substitute for proper land
preparation, irrigation, and other crop management practices
necessary to obtain a good stand of a vegetable crop. Precision
seeding simply allows the vegetable grower to reduce cost and
increase reliability of his crop production. Some of the
advantages of precision seeding are:
- Reduced seed costs, because only seed that is needed is sown.
- Greater crop uniformity, because seed is equally spaced. This
often leads to uniform and high quality produce, fewer harvests,
and greater yield. Uniformity is particularly important when
once-over harvest is practiced.
- Improved yields of 20 to 50% because each plant has optimum
space for growth and development.
- More uniform planting depth and less scatter because seeds are
dropped shorter distances.
- Reduced or eliminated thinning.
Precision seeding also has limitations:
- Seedbed preparation is critical.
- Seed must be more vigorous because each seed must emerge and
does not have the benefit of many seedlings pushing upward to
- More management is required.
- Equipment (seeders) costs are increased.
- Equipment parts may not be readily available.
Types of Precision Seeders
There are 6 types of precision seeders. Each has advantages and
- Belt type - Represented by the Stan-Hay seeder.
Circular holes are punched in a belt to accommodate the seed size
and holes are spaced along the belt at specified intervals.
Usually coated seed improves the uniformity of this type of
seeder. Seeds that are not round are difficult to singulate.
Spacing is not as uniform as with a vacuum seeder. This planter is
used with seeds of tomato to watermelon seed size.
- Plate type - Represented by the John Deere 33. Seeds
drop into a notch in the plate and are transported to the drop
point. Most spacing is achieved by gearing the rate of the turn of
the plate. Seeds that are not round are difficult to singulate.
The plate type is used with seed sizes of lettuce to snap beans.
The long drop from hopper to soil results in a fair amount of seed
- Vacuum type - Represented by the Gaspardo, Heath,
Monosem, Stan-Hay and several other seeders. Seed is drawn against
holes in a vertical plate and is agitated to remove excess seed.
Through a combination of gears and hole number per plate, various
spacings are achieved. Coated seed should not be used in these
planters. There are models of Gaspardo seeders that plant small
(up to watermelon) or large seed (cucumber to snap beans.)
Stan-Hay and Monosem have seeders that can seed both large and
small seed (lettuce to beans). Heath has a wide range of seed
sizes but does not singulate well.
- Spoon type - Represented by the Nibex. Seed is scooped
up out of a reservoir by small spoons (sized for the seed) and
then carried to a drop shoot where the spoon turns and drops the
seed. Spacing is achieved by spoon number and gearing. Spoons are
available for a wide variety of seed sizes.
- Pneumatic type - Represented by the International
Harvester cyclo planter. Seed is held in place against a drum
until the air pressure is broken, then it drops in tubes and is
blown into the soil. This planter is recommended only for large
vegetable seed like sweet corn and snap beans.
- Grooved cylinder type - Represented by the Gramore
seeder. This seeder requires round seed or coated seed that is
made round by coating. Seven seeds fall from a supply tube into a
slot at the top of a metal case into a metal cylinder. The
cylinder is turning slowly and as it reaches the bottom of the
case, the seeds drop out of a diagonal slot. By combination of
forward speed and turning rate, the seed is placed at desired
increments. This planter can be used with seeds no larger than
pepper and works best with coated seed. This planter is used with
small seed (lettuce to pepper).
Before buying a precision seeder, evaluate all other aspects of
crop production to ensure that they are being managed to the fullest.
Precision seeding requires good seedbed preparation to provide a
uniform environment for the seed to swell, germinate and emerge. Bed
shaping is generally considered essential for precision seeding.
Irrigation is also important because lack of moisture may stall or
stop seedling emergence and reduce uniformity. Note: Stan-Hay belt,
Nibex, Planet Jr., Earthway and Gramore make hand push models.
Good, quality seed should be purchased. Precision seeding is no
substitute for good, uniform germination.
Weed and other pest management is more critical with precision
seeding because vegetable crops are seeded at exact populations for
maximum yields. Deviations from this population, as when pests kill
crop plants, result in reduced yields.
Speed of planting will depend on the seeder, but operation of a
seeder above recommended speeds results in reduced uniformity, seed
scatter, and poor stands. See instructions for respective seeds for
information about speed. Regardless of the seeder, check seeder
frequently (every 0.5 to 1 acre) to ensure proper seeding.
Precision seeding results in:
- Better yields
- Reduced thinning
- Reduced seed cost
- Less crop injury during thinning
- More uniform crop plants and harvest
- More efficient harvest and packing
- Improved weed control (less vacant spots for weeds to grow)
- Higher income per acre
North Carolina Cooperative Extension Service
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June 30, 1914. Employment and program opportunities are offered to
all people regardless of race, color, national origin, sex, age, or
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Carolina A&T State University, U.S. Department of Agriculture,
and local governments cooperating.