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Farming 101: How to Plant Corn

Whether it’s your first turn at planting corn or you are an experienced producer who could use a brush-up on the basics, here are a few tips to consider.

The first step in successful corn planting is understanding the land. Soil type matters, as does slope and drainage of the field.

Flatlands are more suited to strip tillage that will aid in soil warming and drying, compared to sloped fields that are more suited to a no-till approach, according to Mark Licht, Iowa State University Extension and Outreach cropping systems specialist. Corn can be planted directly into no tilled residue if the field is well drained with at least a 5% slope. Flat areas with prairie potholes that can pond excessively in heavy rains simply may not be suitable for corn production.

What to plant

The next step is choosing the right seed. There are many varieties on the market, all developed with different goals in mind. If planting early, a full maturity variety will allow for early season vigor and quick fall dry down. If planting is late, an earlier maturity variety is desired to wrap up the growing season before fall.

You may want a trait package that includes herbicide or insecticide or choose a more conventional variety and make applications as the season dictates.

Picking a seed company is part of the decision. Some companies give a discount for quantity if you buy all your seed in a given year from them. Others may give a loyalty discount if you buy from them year after year. One of the advantages of consistently buying from the same company is familiarity with the product line-up. That may help navigate the overwhelming number of options, especially for the new producer.

Row spacing and seeding rate

Debate about the advantages of a 20-inch or 30-inch row is ongoing and depends in part on the hybrid genetics of your seed. Your seed salesmen can be of assistance in advising you as to row spacing and expected seed rate response.

Licht says 33,000-38,000 seeds per acre is an ideal range for much of the Midwest. A higher rate may maximize yield, but a lower rate may be more economical when factoring in the cost of seed. Watch the season-long weather report. Plant lighter in a dry season so there is less competition for moisture. In a wetter year, you can bump up your rate.

When to plant

Some old farmers may tell you it’s time to plant corn when the oak leaves are the size of squirrel’s ears. Others are married to a particular date no matter what or just want to beat their neighbor to the field. But Licht says there are more reliable ways to determine the right time for planting.

Soil temperatures need to be at least 50°F. with a 5- to 14-day warming trend ahead. Field moisture needs to be adequate to germinate the seed, but not so wet it hampers plant emergence or vigor or causes equipment to create unnecessary compaction.

Federal crop insurance dictates when you can start planting in your state and qualify for the program. In Iowa, it is April 11.

Licht says many producers get into more trouble on the second field they plant. “They wait and follow directions on the first field, then the spring rains come, and they see a two-day window, so they hit the second field too soon. When you think you’re ready, wait another one-half day. You’ll be better off.”

Today’s 24-plus-row planters finish the job much faster than some expect, so don’t panic over the passing rainy days. Licht says you will start to see yield declines if you’re not done by May 11, though those declines are not significant until around May 20.

Using the right equipment

The large planter is ideal for large fields with no fencerows, but it is not for everyone or every farm. Be sure to choose the right size planter for the size of your operation and your landscape. Licht says a standard planter from your dealer will generally suffice, at least to start. Various attachments, like row cleaners, starter fertilizer, and insecticide delivery systems can be added later.

“Make sure your planter can move residue out of the row, and the depth gauge wheels work properly,” he says. Just the right amount of down pressure is needed to plant effectively without causing compaction, and that varies according to soil type and organic matter.

Soil fertility will determine whether or not to apply a starter fertilizer when planting, so it is important to know your soil test levels.

Planting day

Set up your planter with your desired seeding rate and make sure it is set for the right seed depth. Licht recommends 2 inches. “If it’s dry, that’s deep enough to get moisture. If it’s wet, it can get out of the ground rapidly.”

As you are planting, make sure you get the furrow closed and you are not creating sidewall compaction. Licht recommends getting out of the tractor every four to six hours to evaluate how the planter is performing. Settings that worked one day, or in the early morning, may not be as effective after temps and breezes have warmed and dried the soil.

Stand assessments

Once the field is planted and the corn is growing, be sure to check the emerging corn and count the plant population. Are there doubles? Is the seed spacing what it should be? Are there skips? Why?

Understanding what you have will help you manage potential problems through the growing season. Weak root systems from compaction can lead to lodging in heavy winds, and a sparse stand is open to weed competition. So, walk your field, evaluate your work, plan how to manage your crop, and make adjustments for next year.

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