The Risks Associated With Planting Corn Before the Optimum Window - MN, ND, SD
Warm temperatures this spring have created the opportunity for growers to get into the field much earlier than normal.
Planting corn early has many benefits, which can include: more days for growers to plant, more days for plant development,
earlier pollination to help avoid heat stress, shorter plant height which can result in improved standability, as well as earlier
maturity and faster dry down. These benefits are significant when compared to late planted corn. However, planting that
occurs prior to the optimum planting window, even when conditions are fit, incurs some risk. For instance, cold temperatures
or a frost after emergence could impact yield, and crop insurance may not provide full coverage.
Optimum Planting Windows
The optimum planting windows for corn in
Minnesota, North Dakota, and South Dakota range
from late April to mid-May (Tables 1 and 2). Planting
before the optimum window may subject corn seed
to cold stress that may affect yield potential.
The optimal corn planting dates for Minnesota are
based on studies from 1988 to 2003 at Lamberton,
MN, which indicated that planting dates ranging
from April 21 to May 6 produced yields within 1% of
the maximum4. These results are supported by a
recent study from 2009 to 2011 at Lamberton,
Morris, and Waseca, MN, in which yield was
optimized, on average, with planting dates of April
25 to May 10. In the ten instances when planting
occurred prior to April 18 in these studies, yields
were 82 to 100% of the maximum (94% was the
average). Thus, planting earlier does not
consistently guarantee maximum yields.
Germination, Emergence, and
Early Growth
Table 1. Optimum Planting Dates for Minnesota1 and
North Dakota2.
State
Section
Optimum Planting Dates
Minnesota
Southern
April 21 - May 6
Central and Northern
A few days later than Southern
Most Regions
Last week of April - May 15
North Dakota
Sources: 1University of Minnesota Extension; 2North Dakota State University Extension Service.
Table 2. Corn Yield Response to Planting Date in South
Dakota3.
Relative
Maturity
Average planting date
April 17
(MN rating)
101 - 103
day (early)
April 27
May 7
May 17
119
-0.6
109
-1.6
114
-1.1
Average yield (bu/acre)
130
132
131
132
112 - 118
If temperatures get cold after planting, imbibitional
143
145
141
131
day (late)
chilling injury is a risk. Seed imbibition occurs when
water is absorbed into the seed and the seed swells.
Average
137
139
136
131
Water intake activates enzymatic processes, such
3
as increased respiration and cell duplication, which Source: Berg, R., et al. SE South Dakota Experiment Station.
eventually result in germination and emergence. If
the imbibed moisture comes from a cold source, such as melting snow or a chilling rain, the
cell membrane can become rigid and rupture. This may result in damaged or aborted
radicles, lower germination, and delayed seedling growth (Figure 1). Such damage may
limit or prevent nutrient uptake, restrict normal seedling development, and allow for soil
disease and pest entry.
Even if chilling injury does not occur, cold temperatures may still slow the uptake of water
into the seed. Germination will not occur until the seed has taken up enough water and
soil temperatures return to 48 to 50° F. If soil temperatures remain below 50° F for two
weeks, emergence problems are likely to occur5. After the radicle (first root) breaks
through the seed, it is no longer protected. Microorganisms can enter the seed where the
Continued on next page
1 / 2
May 27
Daily
yield loss
from
May 7
Figure 1. A corn seedling that
suffered from chilling injury.
Monsanto Technology Development & Agronomy
The Risks Associated With Planting Corn Before the Optimum Window - MN, ND, SD
Continued from page 1
radicle broke through, which could cause the seed to rot. In addition, seeds that do survive may not have much vigor due to depletion of
the seed reserve. Finally, if corn emerges without problems and cold weather occurs after the 2 to 3 leaf stage (V2-V3), Dr. Nafziger of the
University of Illinois indicated there may also be temperature-related damage that can have a negative effect on yield potential6.
Return of Cold Weather
Many growers who have already planted, or are thinking of planting early, may be wondering what the chance is for temperatures to return
to normal. That prediction is difficult to make, but historic weather data indicates that warm temperatures in March and the beginning of
April are not common. Average temperatures for this time of year consist of lows in the low-30’s and highs in the upper-40’s. As an
example, historical temperature data for Waseca, MN from 1982 to 2011 is listed in Table 2. In addition, the median frost date for Waseca,
MN7 is May 4, and the average last spring freeze date for
Fargo, ND8 is May 13.
Crop Insurance
Crop insurance payments from incurring losses can also be
affected by planting date. Crops planted before the earliest
planting date, specified by your crop insurance provider, will
not be eligible for replant payments, but can still receive full
coverage for yield or revenue loss9,10.
Table 2. Average Temperature Data (Fahrenheit)
for Waseca, MN11 from 1982-2011.
Day
April
1
48.5 30.6 39.5 2
48.9 31.1 40.0 3
51.5 30.6 41.0 4
49.9 28.7 39.3 5
49.6 29.9 39.8 6
52.2 30.9 41.5 7
51.2 31.0 41.1 8
51.7 29.9 40.8 9
50.0 29.5 39.8 10
52.0 30.8 41.4 11
54.0 33.3 43.6 12
53.7 33.5 43.6 13
52.7 34.2 43.5 14
56.9 35.4 46.2 15
58.5 36.3 47.4 16
58.0 36.9 47.5 17
56.6 34.2 45.4 18
58.5 36.6 47.6 19
62.6 38.2 50.4 20
59.0 38.3 48.7 Sources
1Coulter,
J. March 20, 2010. Plan now for successful corn planting. Minnesota
Crop News. University of Minnesota Extension; 2Corn production guide. North
Dakota State University Extension Service. A-1130. Online at http://
www.ag.ndsu.edu; 3Berg, R., et al. 2001. Date of planting corn. SE South Dakota
Experiment Farm Progress Report 41:37-42; 4Coulter, J. March 26, 2012.
Planting date considerations for corn. Minnesota Crop News. University of
Minnesota Extension; 5Nafziger, E. March 17, 2000. Planting corn-how early is
too early? University of Illinois Extension. The Bulletin; 6Nafziger, E. April 4, 2008.
Thinking about corn planting date and population. University of Illinois Extension.
The Bulletin. Issue No. 2, Article 7; 7Minnesota Climatology Working Group. State
Climatology Office, DNR Division of Ecological and Water Resources, University
of Minnesota. Online at http://climate.umn.edu; 8Last spring freeze climatology.
March 27, 2012. High Plains Regional Climate Center. Online at http://
www.hprcc.unl.edu; 9Edwards, Williams. February 2012. Important crop
insurance dates. Iowa State Extension and Outreach. Ag Decision Maker. Online
at http:/www.extension.iastate.edu; 10Schnitkey, G. March 20, 2012. Impacts of
planting before crop insurance earliest planting date. University of Illinois
Department of Agriculture and Consumer Economics. FarmDOC Daily. Online at
http://www.farmdocdaily.illinois.edu; 11Midwestern Regional Climate Center.
http://mrcc.isws.illinois.edu. Additional Sources Used to Create this Publication:
Iowa State University. 2006. Did the recent cold weather affect corn germination
and seedling growth? Integrated Crop Management. May 1, 2006; Leopold, A.C.
1983. Volumetric components of seed imbibition. Plant Physiology. 73 (1983) 677
-680; Nielsen, R.L. March 2001. Thoughts on Corn Planting Dates. Purdue
University Department of Agronomy. Corny News Network. Nafziger, E. April 10,
2009. Corn Planting Date Revisited. University of Illinois Extension. The Bulletin.
Issue No. 3, Article 8.
Individual results may vary, and performance may vary from location to location and from year
to year. This result may not be an indicator of results you may obtain as local growing, soil and
weather conditions may vary. Growers should evaluate data from multiple locations and years
whenever possible.
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Leaf Design℠ is a servicemark of Monsanto Company. ©2012 Monsanto Company. AMB03212012; ABT04022012
2 / 2
Maximum
Minimum
Mean
Temperature Temperature Temperature
Month
Source:
11Midwestern
Regional Climate Center.
Monsanto Technology Development & Agronomy