Corn Late Planting Options
May 29, 2003 10(11):83-84
Joe Lauer, Corn Agronomist
The economics of corn grain production make June planting in Wisconsin marginal
due to lower yield and high grain moisture. In Wisconsin, yield of corn planted
in early June decrease at the rate of 3% per day delay. In most years the latest
economical planting date for corn grain production in northern Wisconsin is June
1, while for southern Wisconsin corn should not be planted for grain production
after June 10.
Maturity switch dates for corn in southern Wisconsin are May 20 and June 1 where
on each date hybrid maturity should be 5 to 10 RM units shorter-season than the
"full-season" hybrid used for the field. The decision depends upon drying
cost and grain price. When grain prices are low and drying costs are high, switch
dates are earlier. For northern Wisconsin there is only one maturity switch date
on May 20. Yield is not different between full- and shorter-season hybrids when
planted in June, but shorter-season hybrids should be used to better manage risk
from fall frost.
Corn can still be planted in June, but in most years it should be intended for high
moisture grain or silage use. In general silage yield decreases 31 to 41% as planting
date is delayed from the optimum date to June 20. The economic trade-offs are difficult
to establish for late planted corn silage. Milk per acre is more affected than silage
yield due to the low grain content of the silage. Most of the silage yield reduction
is due to grain yield reduction thereby decreasing the energy content of the silage.
In most years, planting date and maturity switches for corn silage use should be
the same or slightly later than those for grain use. Although there may be more
flexibility in years where grain prices are low when it may be possible to add grain
to corn silage for later planting dates thereby raising quality. The economics of
this management decision must be carefully considered.
Deciding when to quit planting corn is not an easy decision. In some years we can
have a late fall frost and later planting dates can do fairly well. A number of
factors should be considered when deciding whether or not corn should be planted
- Corn production costs (Drying costs): Shorter-season hybrids reduce the risk of
immature and wet grain in the fall. But, ultra-short- and short-season corn hybrids
must have adequate yield potential to recover production costs.
- Corn price: Higher corn prices make planting later into June with shorter-season
hybrids more attractive.
- Other uses: Corn used for other purposes such as high moisture grain or corn silage
can be planted later into June than corn harvested for grain. High moisture grain
and silage allow the use of longer season hybrids with greater yield potential.
- Other cropping alternatives: Compare the relative yield potential of an alternative
crop for a given date with that of late planted corn. For example, corn yield potential
declines at a faster rate than the yield potential of soybeans. Other crops to consider
include sunflowers, buckwheat, and sorghum-sudan grass.
- Environment: First fall frost date and fall drying conditions influence your decision.
Years that are longer and warmer thGeneral guidelines for June corn planting in
south and south central Wisconsin are:
Less flexibility for corn planting dates in June is observed in northern Wisconsin.
- Corn for grain can be planted until about June 1-10;
- Corn grown for high moisture corn and silage uses can be planted until about
After June 20, consider switching to a different crop.