Recent conversation on Farmers for the Future centered around a very good question: just how early is too early to plant corn?

Since the 1970s, the time for planting corn in the spring has moved up 10 to 14 days. The ability to plant earlier is mainly attributed to advances in plant breeding and seed treatments, and perhaps, changes in climate.

A recent article in “Top Crop Manager” states that planting dates vary from April 15-24 across the Corn Belt, depending on soil conditions. Although breeding and seed treatments have allowed for earlier planting, it’s still a good idea to watch the weather. Seed is most vulnerable during its first few days in the soil, so you certainly don’t want to put it in unfavorable conditions early on.

One tip included in this article involves grabbing a clump of soil and watching how easily it crumbles. If the soil stays in a ball, conditions are not right for planting. If it crumbles easily, the soil is fit for planting.

It’s also very important to look at farm insurance policies as they relate to planting dates. Make sure you have looked at the specifications for the “do not plant before” dates — if you plant outside those dates, your insurance coverage could be jeopardized.

In the end, when you plant is truly is a judgment call based on weather and soil conditions. You know your fields better than anyone. And as the article states, it’s very rare that judgment leads a farmer too far beyond the limits.

To read more of the “Top Crop Manager” article, click here. For a helpful table provided by the University of Nebraska Extension on planting dates, click here.

Despite the trend of farmers planting earlier and earlier, research results recently released by Iowa State University Extension agronomists show that farmers have nearly a month-long window to plant their crops and still realize 95 percent of the crop’s yield potential. The optimal start dates to begin planting corn, according to this study, range from April 11 in southern Iowa to April 15 in northwest Iowa.

ISU agronomists conducted research on seven sites for three years – 2006, 2007 and 2008 – for a total of 21 site-years. Based on yield data obtained, recommendations have been developed to achieve maximum yield possible in relation to planting date for each of three regions across the state. Each region had a different window of time that optimized the yield, on average. A summary of these windows, as published in Integrated Crop News, follows:

Northeast region (red):
This region has the narrowest planting window due to the need to maximize the length of the available growing season. Grain yields begin to drop off more significantly here than the rest of the state if plantings are too late. We recommend planting between April 12 and May 2 (95-100 percent yield window) or between April 12 and 30 (98-100 percent yield window). The dataset is limited for plantings before April 12 in this region, hindering our ability to make recommendations prior to this date.

Northwest and central region (yellow):
This region has a flatter yield response to planting date than the other regions. In other words, planting date does not appear as important of a management practice here as in other parts of the state. We recommend planting between April 15 and May 18 (95-100 percent yield window) or between April 15 and May 9 (98-100 percent yield window). Again, information for this dataset is limited for plantings before April 15 in this region, diminishing our ability to make recommendations prior to this date.

Southern region (blue):
The yield response in this part of the state is presumably related more closely to rainfall patterns and soil moisture than the length of the growing season since this typically is not a limitation as it is in the northern part of the state. We recommend planting between April 11 and May 13 (95-100 percent yield window) or between April 17 and May 8 (98-100 percent yield window).

An expanded article, with more detail specifically on the methods behind this project and the development of recommendations can be found on the ISU Corn Production website.

A big thank you to all of the Farmers for the Future members who responded to our recent question, “Just how fast is too fast?” in regards to planting.

Corn and soybean plants are subject to more than 1,000 variables each growing season. Proper planting is the most crucial variable and can have the most impact on performance. Below is a chart that shows the differences of seed placement when traveling 5.5 mph and 6.5 mph.

Many of the members who responded to the question answered that they think it’s best to take your time when planting, as the benefits for a slower speed will be present at harvest. They couldn’t be more right.

If you have any questions we can help answer regarding planting, please let us know. Also, if you’re looking for tips and information on spring planting, please take a moment to read our recent blog posts on planting preparation:

Planter Preparation

Top 5 Tips to Maximize yield

Tips to Deal with Soil Compaction

Top 10 Reasons to Avoid Soil Compaction

There are many things that require your attention as you prepare to head back into the fields, but one of the more important things you can do is get your planter well prepared for planting.

Below is a check list of important steps to take when preparing your planter for the field:  

1. Check the drive trains; make sure they are not rusted or stiff.
2. Check the shaft bearings and sprocket bearings for their shape and condition. They should be well lubricated.
3. Clean and inspect the chemical meters used for seed treatments on the planter.
4. Check the opener blades; make sure they are not worn.
5. Check the sprocket teeth for wear.
6. If equipped, make sure the vacuum meter system is clean and seals are not worn to ensure proper metering.
7. Use the owner’s manual extensively for calibration.
8. Follow all hourly service requirements and greasing requirements.
9. Stop by the dealer or visit the equipment manufacturer’s web site to learn what is new.
10. In the field, dig to expose seeds in the row to be sure the planter is operating correctly. This may help avoid an erratic stand after emergence. Confirm desired seed depth and seed-to-soil contact.

For other important tips as you prepare for planting, see our blog, Planting Preparation, (you’ll need to scroll down a bit) and as always, please post any questions you might have that we can help with in the field below.