<img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=804366656390463&amp;ev=PageView&amp;noscript=1">
Iowa Corn Growers Association
Corn FAQs page banner

Corn FAQs

Iowa's Corn Production


Last year, Iowa corn farmers grew over 2.4 billion bushels of corn on 12.9 million acres of land. Yeah, that’s a lot of corn. 

Is all the corn grown in Iowa sweet corn?

You wish! Less than 1 percent – or only about 3,400 acres of sweet corn is grown in Iowa each year. Most of the corn you see growing in Iowa is field corn, which is used to make fuel, feed, food and thousands of other everyday products.


Iowa has been the king of corn for almost two decades. In an average year, Iowa produces more corn than most COUNTRIES! Seriously, Iowa grows about three times as much corn as a country like Mexico. And Mexico is huge! Just goes to show Iowa grows a substantial amount of corn.

Why is corn Iowa's leading crop?

Corn has been the top crop in Iowa for more than 150 years running! And that’s not because Iowa farmers just can’t think of anything better to grow. It’s because Iowa is the best place on the planet to grow corn.

  • Iowa has a growing season that is long enough and warm enough to suit corn production.
  • Iowa usually receives enough rain to support healthy corn production.
  • Iowa has deep, rich soils that suit corn's needs.
  • Iowa also produces lots of livestock whose waste includes nutrients that are key to fertilizing fields for better corn production.
  • A wide variety of corn hybrids are available that do especially well in Iowa's environment.

Planting Corn

When is corn planted?

Corn is planted when the soil is warm enough to germinate the seeds but not so early that the young plants are likely to be damaged by frost. In Iowa, this can be in early April for the state's southern counties, but it can be several weeks later for the state's northern counties.

Where does corn grow?

Corn grows on every continent except Antarctica. Most corn is grown in middle latitudes (between 30 and 45 degrees), about equal to the area north of New Orleans and south of Montana in the Northern Hemisphere.

How big is an acre?

Officially, one acre is 4,840 square yards or 43,560 square feet. That’s about the size of a standard football field.


Iowa corn growers grow an average of 200 bushels per acre. Nationally, the average is 175 bushels per acre. 

Harvesting Corn

When is corn harvested?

In Iowa, some farmers begin harvesting corn by mid-September, though most of the harvest is takes place in October. In a cool year, when the corn matures more slowly, much of Iowa's crop isn't harvested until November. Harvest times can vary a great deal because different corn hybrids take different lengths of time to mature. Even when plants are physically mature, farmers might wait to harvest them until corn kernels have dried further so that the corn can be stored for longer periods of time.

How big is a bushel?

A bushel began as a measurement of volume, but the accepted standard for a bushel of corn is now measured in weight (56 pounds). This weight is specifically for shelled corn (after the husks and cobs are removed). Think of it as about the size of a large bag of dog food.

When corn is harvested, what happens to the cob and the husks?

Modern combines strip the husks off each ear and remove the kernels from the ears as part of the harvesting process. The combine spreads the husks and cobs back onto the field as it moves but keeps the grain in a holding tank until it can be unloaded into a truck. In the field, the cobs and husks are still valuable because they help maintain good soil fertility and structure, just as compost and mulch do in home gardens.

About the Corn Plant

Where does corn come from?

The first corn plants seem to have appeared in Mexico, having descended from a plant called teosinte. The earliest known ears of corn were tiny – only a few inches long. Millenniums of breeding, first by Native Americans, then by early pilgrims and modern scientists, have resulted in bigger, fuller ears of corn. So be thankful the next time you butter up a big, delicious ear of sweet corn.

How many ears grow on a corn plant?

Different corn plants have different numbers of ears, but much of the field corn grown in Iowa is bred to develop just one large ear rather than several incomplete ears. This approach usually yields better total production.

How many kernels are there on an ear of corn?

The number of kernels per ear can vary from 500 to about 1,200. A typical ear has about 800 kernels, according to corn experts. Imagine how many kernels are found in an acre of corn!

How tall is a typical corn plant?

A typical corn plant can be anywhere from five feet to 12 feet tall. That’s over a story high! Under good growing conditions in Iowa, plants are commonly about eight feet tall by midsummer. A healthy corn plant's root system will reach about 6.5 feet into the ground!

Why are there silks on corn?

The silks on corn are essential for pollen from the tassels to fertilize the plant. Each silk will convey pollen to one site on a developing ear of corn, making it possible for that site to develop into a kernel of corn. If it's too hot in the summer, the silks can dry out before all the sites on a corn cob are fertilized. As a result, there will be gaps on that ear of corn where no kernels developed because they weren't fertilized.

Uses for Corn

How is Iowa's corn crop used?

Most of Iowa's corn goes into animal feed and ethanol production, but it’s also used to make starches, sweeteners and over 4,000 everyday products. When you think about it, corn is used to make just about everything!

How is corn used for livestock feed?

In livestock feeding, one bushel of corn converts to about eight pounds of beef, 15.6 pounds of pork or 21.6 pounds of chicken. The next time you eat a bacon cheeseburger or grilled chicken breast, you can thank corn.

How much ethanol do you get from a bushel of corn?

One bushel of corn can produce about 2.8 gallons of ethanol, and the process also yields about 17 pounds of a high-protein animal feed known as dried distillers grains with solubles (DDGS). Corn and ethanol production are now so efficient that it takes less energy to grow the crop and process it than the amount of energy in the ethanol itself.

Is it true that there's corn in hundreds of products?

Corn ingredients can be found in almost 4,000 everyday products – like lipstick, paper, plastic water bottles, tires, crayons and beer. That doesn't include all the meat, dairy and poultry products that depend on corn for livestock feed.

Buying Corn and Corn Products

Who should I contact to buy corn and corn products?

We partner with the U.S. Grains Council who can help connect you with a seller of grain. Below is a list of resources to help you through the process:

For a list of Iowa Suppliers:
Iowa Directory of Exports

For a list of U.S. Suppliers:
U.S. Grains Council - Commercial Grain Exporters

© 2024 Iowa Corn Promotion Board/Iowa Corn Growers Association. All rights reserved.