Narrow Row Corn
Marion with Francis
Myths of 15 and 20-inch Row Corn

  • More bushels per acre
  • Less weeds
  • Less erosion
  • Plant and harvest faster
  • More bottom line profit!

In 15" and 20" rows, plant spacing becomes more uniform. This reduces in-row competition
between plants and improves sunlight interception (see chart below).
Research data from Texas actually shows a higher yield
advantage to 15-inch corn rows over 30-inch than does
University of Illinois research data.  Argentina and Brasil are way
ahead of the United States in the adoption of narrow row corn.
Research data from Texas actually shows a higher yield.
It takes a special hybrid to grow narrow row corn.
Premier hybrids in wide rows tend to be Premier hybrids in
15 and 20-inch rows.
Narrow row corn requires narrow tires.
Research from Ohio State indicates wider tires have a bigger
footprint thus reducing compaction and increasing yields.
"The poorer the soil the bigger the yield kick to 15
or 20-inch row corn!"
George Roberts - Trovoli, Illinois
Switched to 20-inch rows in 1989

"When we finished harvesting our 15-inch rows and
pulled into the field of 30-inch rows, it looked like
there was one row missing and so much wasted
 Dave Sweeden, Farmer - Streator, Illinois
Seed costs increase in 15 and 20-inch rows due to higher
Significant yield advantages have been documented even
when both row spacings are compared at the same
The yield advantage of 15 and 20-inch row corn is minimal.
In 394 side-by-side farmer field trials, 15-inch row corn
outyielded 30-inch row corn by an average of 12.3 bushels
per acre.
Row Width
Average Plant
30"  at
=  7.5"
20"  at
=  11"
15"  at
=  15"
Based on farmer run research and experience, correct implantation of these row spacings
will provide significantly higher yields (see chart below).
No. Yield
15" Percentage
At $2 Bushel
"Narrow rows will not penalize in dry years"
John Bradley, researcher - Milan, TX
Now with Monsanto
Benefits of 15 and 20-inch Row
Farmer Split Planter / Side-by-Side Comparisons
New practices, new equipment could usher in a new type of corn production
The move from 40- and 38-inch row corn down to 30-inch rows is credited
as one of the major factors contributing to the steady increase of corn yields
over the past several decades, along with improved hybrids, and better
herbicides and fertilizers.
The next major breakthrough may be just over the horizon, if 15-inch
"ultra-narrow row" corn fulfills its early promises of improved yields and
weed control advantages, similar to the gains 15-inch soybeans have
There's a generally accepted rule of thumb among corn rsearchers that says
you'll average a 1-bushel-per-acre yield increase with every inch of row
spacing you decrease.  While quite a few studies have focused on 20-inch
corn, researchers involved with 15-inch corn see no reason to consider 20
inches as a self-imposed lower limit .  15-inch row corn, they say, offers the
best balance of yield potential, weed control and harvesting ease.
Marion Calmer is an Alpha, Illinois, farmer who operates his own 1,300 acre
independent research center based on "real world" field trials.  He is an
enthusiastic proponent of ultra-narrow row.
"We have been doing extensive work with ultra-narrow row corn and believe
beyond the shadow of a doubt that 15-inch rows offer a yield advantage,"
says Calmer, who has grown 15-inch corn in field conditions for several
Gord Scheifele, a research scientist at the Ridgetown College of Agricultural
Technology in Ridgetown, Ontario, agrees.  He says test plot evaluations
show "significant incremental increases in yields" compared to 20-inch corn.
Purdue studies acknowledge the potential for yield gains in the "bushel per
row inch"  range, although noting the more consistent yield responses to
ultra-narrow row corn appera to ocur in the Northern Corn Belt.
Farm Forum - Spring 1997
Francis Childs
Manchester, Iowa
World Record Corn yield!
441 bu/ac - 20" rows
2008 15" Advantage report
Four Oaks Sinele Farms -Southern Illinois
Harvest Date      10-Nov-08
Seed type           Row spacing         Bu        Acres        Bu/Acre         15"
Pioneer 32T84          15                  115         0.4            287.5                 22.5
Pioneer 32T84           30                 106         0.4            265

Pioneer 32T84          15                  119.4      0.4            298.5                 34.5
Pioneer 32T84          30                  105.6      0.4            264
Pioneer 32T84          15                  117         0.4            292.5                 28.5
Plot planting date, May 5                         Average advantage           28.5
"All indications are that I should have
switched to 20"rows sooner!"
Great Residue!
Calmer Corn Heads, Inc.                                                      email;
Mailing Address;                                 Physical Address;
P.O. Box 9                                              3056 N. 700th Ave                 
Alpha, Illinois  61413                           Lynn Center, IL  61262
Copyright © 2009 Calmer Corn Heads. All Rights Reserved.
Better Harvesting
Through Innovation
Phone : (309) 629-9000
Fax : (309) 629-9001
Email :
Calmer Corn Heads
Better Harvesting
Through Innovation
Moving To Narrow Rows
Moving To Narrow Rows
12, 15, and 20 inch
Marion Calmer is also known for his
research on beans in 15"rows
1. In selecting the number of row units for planters and corn heads farmers prefer an even number of
rows and a 1:1 or 2:1 ratio.  Example: 24 Row Planter and a 12 Row Corn Head.
2.  Rows in 15 and 20 inches allow for slower meter
speeds, which should result in better spacing
performance.  Some Kinze owners say that in 15
and 20-inch rows the meter speed is too slow and
a round seed when released by the finger
sometimes bounces back through the window like
a basketball causing skips and low populations.  
Some farmers remove every other finger for
15-inch rows.  Also there are some new
experimental backing plates with smaller windows
that reduce seed bounce and skips.  
(Kinze part #GD 11788) Case IH planters use a 36-hole drum for 30 and 36-inch rows but need a 24 hole
drum for 15 and 20-inch rows to maintain optimum drum rpm.  Raising air pressure or vacuum can help
reduce skips.
3.  Setting planter maker 5 inches wider than the row spacing will help avoid knocking down rows at
4.  If you have an odd numbered row planter, planting the center row into a deep marker trench could
result in yield reductions within that row.
5.  Planting into compacted tire tracks may cuse some yield reduction.  Reduced tractor weight, coulters,
track eliminators, tracks, big tires, and low air pressure in radial tires will help alleviate compaction and
tread patterns created at planting time.
6.  John Deere 15-inch planters drive over the splitter row before it's planted.  Kinze 15-inch planters drive
over the row after it's planted.  Kinze sells a tire that has no center ribs on it to help alleviate compaction
directly above the seed.
7.  Tall, wide tires with big footprints decrease soil compaction.  Tall skinny tires with small footprints
increase soil compaction.
8.  Genetics - top yielding hybrids in 30-inch rows tend to be the top yielding hybrids in 15 and 20-inch
rows.  It takes longer to burn the fog out of a 15-inch row in the summer and there is more soil moisture,
so select hybrids with good resistance to stalk, rot, and leaf diseases.
9.  Some farmers growing ultra-narrow row corn mix liquid insecticide with starter fertilizer and inject the
mixture into the seed trench.  Other farmers broadcast liquid (Furadan) insecticide in the plant spike to
5-inch stage of growth.
10. Most farmers in the Central and Southern Corn Belt think optimum planting populations are from
28,000 to 32,000 plants per acre.  Higher population increase your risk of lodging.
11. Most farmers in the Northern Corn Belt think optimum planting populations are from 30,000 to 36,000
plants per acre.
12. Populations - optimum populations in 30-inch rows tend to be the optimum populations in 15 and
20-inch rows.  Recalibration of the corn meter is necessary for 15 and 20-inch rows.
13. Farmers claim they can plant faster with no yield reductions and sometimes get a yield increase
because the corn meters are running too slow when planting 15 and 20-inch rows at 5 mph.
14. In any row spacing, a good job of planting 30,000 plants per acre will have a higher ear count at
harvest than a poor job of planting 30,000 plants per acre.
15. Vertical placement of the seed is probably more important than horizontal placement in 15 and 20-inch
Planting - Narrow Row Corn
Growing Season - Narrow Row
Harvesting - Narrow Row Corn
1. It's best to harvest 15-inch rows with a 15-inch row corn head especially in research plots.  If a 15-inch corn head is not available, you can use a
30-inch row head, which pulls two 15-inch rows together, but there is greater potential for ear loss.  Avoid this potential ear loss by cutting ground
speed. Harvesting early, and using BT hybrids.
2.  Farmers claim they can harvest "downed corn" easier with 15 and 20-inch row headers than with 30 and 36-inch row headers.
3.  Finding the rows at harvest can be challenging in severely wind blown 15 and 20-inch corn.  White corn head divider snouts, a guidance system
and auto header height are helpful.
4.  Farmers say 15 and 20-inch corn heads can pick in any direction.
5.  Shorter divider snouts are available for use on contours.
6.  Farmers claim they can harvest faster in 15 and 20-inch rows.
7.  The yield advantage for narrower rows occurs every year but at different levels.
8. 100 percent of farmers with single chain corn heads stated they performed as well if not better than 2 chain corn heads.
9. Since machinery cost can be higher the yield advantage must be large enough to cover the cost and still have some money left over to make it
profitable.  At our farm we feel it takes 5 bushels per acre to make it profitable.
10. The economics of 15  or 20-inch rows is determined by a math equation considering multiple factors such as: acres, one planter/two crops, one
corn head/two row spacings, cost to modify equipment and savings in weed and erosion control.
Allen Berry looking over Calmer's Corn Head
1. Some research has indicated that uniform plant spacing may explain why the average
stalk diameter has increased in 15 and 20-inch rows.
2.  Narrow rows provide more even distribution of roots during the growing season.  This
should make the plant more efficient in absorbing nutrients and water.  This also helps
reduce erosion.
3.  Narrow rows canapy faster and provide better weed control.                                       
(Weeds don't grow where the sun doesn't shine.)
4.  In 15-inch rows you'll normally see only one flush of weeds due to the quicker canopy, so
spray early.
5.  When spraying with the rows, use the correct wheel spacing and tire size.  12.4 - 54 tires
on tractors or spray coupes work nicely in 15-inch rows.
6.  If correct wheel spacing and tire size is not an option, spray at 0 degrees to the row,
especially in research plots.
7.  A one-pass post emerge Roundup herbicide program does work in 15-inch rows.
8. There's the possibility of an increase in leaf disease because of the quicker/denser
canopy, which holds more moisture between the rows.  Scout hybrids with low resistance to
leaf disease, especially during a wet growing season and treat accordingly.
9. Farmers with experience growing 15-inch corn believe the yield advantage is greater on
poorer soils than on better soils.
Researching 15 & 20-inch Row Corn
1. Doubling back with a 30-inch planter to create 15-inch rows creates twice as much compaction, which can nullify the yield advantage of 15-inch
rows.  Doubling back may be acceptable in demonstration plots but is not acceptable in reasearch plots.
2.  All field operations should be performed in a different direction than planting.  Example: Plant north and south...spray, fertilize, or till east and west.
3.  Ideally, row spacings should be compared at the same planting populations.
4.  Ideally, row spacing should be compared with the same planter and should be equipped and calibrated so that meters operate at the same speed for
both row spacings.
5.  Both 23 and 31 row 15-inch Kinze and 31 row 15-inc John Deere Planters provide a good way to test 15 versus 30-inch.  They have two
transmissions which allows planting of both row spacings at the same time.
6.  When calculating yield data in 15-inch rows, remember that 15 - 15 inch rows = 225 inches which is only 18 feet 9 inches and not 20 feet.
7.  At our farm, test plots with long row length have less yield variability than test plots with short row lengths.
8. We don't do everything correctly on every acre or every research plot.  We are still learning and do not know what ultra-narrow corn's full potential is,
but we know the yield advantage does increase with experience.
12 inch row display at Farm Progress