Supposedly the third week of April is the best time to plant corn here in Northern Indiana, but sometimes conditions aren’t fit for planting or doing any kind of field work that week. In 2012 we started crazy early on March 28th, but it had been 80ºF for two weeks by that time. Conditions were right. But 2013 started out really wet. We didn’t put seed to soil until May 6th. This year, 2014, we started on April 23rd which just happens to be the same day we finished planting in 2012. Readers might recall that 2012 early planting ended up being a precursor to a prolonged drought across much of the United States. In the last few years we’ve had some really different starting dates, so how do we really know when it’s time to plant if the date on the calendar isn’t always the most reliable source?
Moisture
Rain makes grain right? But when it’s time to work the soil you can have too much moisture. You don’t want too little either. Too much water can mean a few things. A tractor could get stuck. That’s way too much moisture. Wet soils compact easier, and we don’t want to force paths for roots and water to close. Those pockets are where roots and shoots find their way around. Too wet often means to cool as well. If we have seeds sitting in cold, wet soil for very long some of them will begin to rot or invite disease. Soybeans will soak up water easily causing a replant situation. Soil that’s too wet also can keep the planter from closing the seed trench back over the seeds, leading to poor seed to soil contact which is very important for germination.
This is just right. A touch dry on top with moisture in the profile where seed will be placed.
Not enough moisture isn’t good either. We don’t have a system of numbers or charts to tell us when the soil moisture is right for planting. This is a boots in the field and hands touching soil type of operation. Like any other task after time you just get a feel for what is right and what is not. We want moisture in the top few inches of soil where we plant around 2″ deep. Moist but not wet, and definitely not muddy. When tillage is used to prepare the seedbed ahead of the planter it’s important to know that the soil will begin to dry out faster. For this reason we don’t run the field cultivator too far ahead of the planter.
Temperature
We have a really fancy device for gauging soil temperatures. It’s a thermometer. Pretty high tech right? We look for a minimum soil temperature of 50°F to begin the planting season. In 2012 that came a month ahead of what is normally considered prime time for planting. This year we happen to be right in that third week of April sweet spot.
Now at some point you just have to go farm even if conditions aren’t perfect. If it’s getting really late towards the end of May or into June in this part of the country we’d probably be out getting things done before we would think about prevented planting acres a couple weeks beyond that. I have a friend in Minnesota who didn’t plant half his farm with cash crops in 2013 because of wet weather.
At the end of planting season we put everything away to where it’s 99% ready to go to the field the next year. So what we are really doing around April 1st each year is waiting for Mother Nature to tell us when it’s time to go. There’s no X on the calendar that tells us we are going to plant that day.
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