Corn planting time is tricky

It is time for farmers to plant corn, an unsettling time when all preparations have been completed and the only thing holding them back is the right weather and field conditions.
Our farmers like to plant corn from the last week of April through about May 10. University data has shown them that, in most years, corn will yield the most when planted then.
However, the farmer has to consider many factors before picking the actual planting date. Soils have to be fit for the seed, not too wet or too cold.
If the soil is unfit at planting, they may have poor emergence and have a field left with an uneven stand. Then they will be faced with the dilemma of a potential replant, more expense and an additional delay in getting a solid stand of corn.
If planting is delayed past this window, then the farmer may have to switch to a different hybrid, which may be limited in availability since many farmers may be switching.
Also late-planted corn runs the risk of pollinating during the hotter part of summer, which may lead to poor seed set.
Corn is a warm-season crop and needs soil temperatures of at least 50 degrees for germination and growth. The cooler the soil temperature, the longer it will take seed to germinate and emerge.
Corn seeds have a greater risk of attack from soil pathogens if the soil is cool and stays wet soon after planting. Pythium is the most common pathogen affecting corn under cool and wet conditions.
There are more than 25 different types of Pythium that thrive in cooler temperatures. Pythium is actually attracted to germinating seeds and growing roots in wet soils.
Most corn seed is treated with fungicides to protect against seedling pathogens such as Pythium. However, if the seed remains in the soil for an extended period or seedlings are slow to emerge, they may then become susceptible to Pythium and other soil pathogens, even with the fungicide.
To avoid slow emergence, farmers often will wait until weather conditions suggest warmer rather than cooling soils in upcoming weeks.
However, they are also aware that waiting may cause later pollination, and waiting may also create a problem if the farmer has several thousand acres to plant.
In some years, soils may be dry enough to plant but are still on the cool side.
In these situations, the farmer has to decide if the soils will warm enough during the next several weeks for adequate germination and emergence.
Otherwise, vulnerable seedlings may not become established and die if an extended cool and wet period moves into the area.
Kernel or disease damage generally does not take out the whole stand but causes uneven emergence and thin stands in parts of the field, which may lead to that haunting question of whether to replant or not.
Soils are still cold in Hancock County.
In many areas, average soil temperatures were in the low 40s last week. They hovered in the low 50s during the weekend.
There were a few brave farmers who planted some fields of corn on better-drained ground before the rain at the end of last week.
However, it appears most farmers are hoping for a warm and dry early May to plant.
As a result, the non-farmer community needs to be patient with farmers who may appear to be restless and a little grumpy. They just want to get their corn planted, soon followed by soybeans.
Lentz is extension educator for agriculture and natural resources for The Ohio State University Extension Service in Hancock County. He can be reached at 419-422-3851 or via email at lentz.38@osu.edu.
Lentz can be heard with Vaun Wickerham on weekdays at 6:35 a.m. on WFIN, at 5:43 a.m. on WKXA-FM, and at 5:28 a.m. at 106.3 The Fox.

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