A kernel of corn

Corn FAQs

Iowa’s Corn Production

How much corn does Iowa produce?

In 2016/2017, Iowa corn farmers grew 2.7 billion bushels of corn on 13.5 million acres of land. At 56 pounds per bushel, that’s over 150 billion pounds of field corn. Yeah, that’s a lot of corn. (Source: PRX, Jan. 2018)

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.

What state produces the most corn?

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 crazy 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.

How much corn is grown on one acre?

In 2016/2017, Iowa corn growers grew an average of 203 bushels per acre. Nationally, the average is 175 bushels per acre. (Source: PRX, Jan. 2018)

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

How Much Corn is On an Ear?

View All Produce Conversions

It can seem frustrating to try a new recipe and not know how much of an ingredient to purchase at the store. Sometimes they call for “1 cup of corn kernels” or “the kernels from two ears of corn”. That’s a fine description if you are using frozen corn or fresh corn respectively, but otherwise, exactly how much corn is on an ear of corn? In order to help make cooking easier we did some experiments to help tell you exactly how much corn you need to buy.

To answer How many ears of corn kernels make a cup we went to the grocery store to check out the produce section. When talking about sweet corn, a small ear tends to measure less than 6.5 inches long and a large ear more than 7.5 inches. Therefore, a medium ear usually falls somewhere between 6.5 and 7.5 inches long and 2 inches across at the widest point. For our test samples we purchased medium ears of corn and headed home to the kitchen.

To answer the question How much corn is on an ear we removed the kernels from medium ears of fresh corn. While the yield of the corn kernels will obviously vary by the size of the cob, it was surprising to see a heavy 1/2 cup to a 3/4 cup result range within the “medium” size corn cobs. More often than not, our medium ears of corn produced 3/4 cup of kernels when cut from the cob.

So if your recipe calls for 2 ears of corn, you can now confidently know that it means about 1.5 cups of corn kernels. And “How many ears of corn do you need for 1 cup of corn kernels” is about 1 and a third ears of corn.

Did you know that corn is technically a grain, not a vegetable; it is a cereal crop that is part of the grass family. The ear is really part of the corn flower and each kernel is a seed. Corn will always have an even number of rows on each cob. Popcorn is a special type of corn grown that when heated it bursts into hot, fluffy kernels – yum! And corn is used to produce fuel alcohol which makes gasoline burn cleaner, reducing air and water pollution.

Now that you know how much corn is on an ear we hope this will take away some of the guesswork when trying to substitute fresh and frozen corn in your favorite recipes. You can also use our conversion tool below for any custom how many corn ears in a… measurements you need. If you de-corn a lot of ears by just using a knife you should definitely look into getting a good corn stripper to greatly speed up the process. I feel comfortable recommending the Kuhn Rikon Corn Zipper since it’s inexpensive, easy to clean and I use it at home!

A Ear of Corn Equals

  • There is ¾ Cup (177 mls) of Corn Kernels in a Ear of Corn

Custom Conversions for Ear of Corn

I need:
You need 1.4 Ears of Corn

What is the Produce Converter?

One of the biggest hassles when cooking and working in the kitchen is when a recipe calls for “the juice of 1 lime” or a similar measurement. Often times when cooking people use bottled juices, pre-sliced vegetables and other convenient cooking time savers. Produce Converter will help you convert the “juice of 1 lime” and other similar recipe instructions into tablespoons, cups and other concrete measurements.

Produce Converter can also be used to figure out how many vegetables to buy when you need, for instance, “A cup of diced onion.” You can use our easy conversion tool to figure out exactly how many onions you need to buy at the store in order to end up with the amount you need for your cooking.

We hope you enjoy Produce Converter and if you have any suggestions for how we can improve it and make your cooking easier please let us know.

Number of Rows Per Ear, Kernels Per Row Matter for Yield

A college-age son once told his dad, a corn breeder, that he figured his dad was busy trying to develop the biggest corn ear possible. The breeder politely told his son that, no, that wasn’t the key to the highest yield possible. The key, the breeder said, was figuring out how to have as many ears as possible. If the ears were somewhat smaller, the sheer volume of them would raise yields if plants could support them.

That’s where we are today, says Dave Nanda, consultant for Seed Consultants, Inc. He believes the future belongs to those who can grow as many as 70,000 plants in equidistant spacing and harvest uniform, if relatively smaller, ears.

Two hybrids: Dave Nanda holds ears from a hybrid with 16 rows per ear on your left, and one with 14 rows on your right. The only ways the hybrid on the right can compensate is by having more kernels per row, or deeper, fuller kernels.

Corn Illustrated 8/5: Corn Diseases Are Out There; Are You Scouting for Them?

In the meantime, however, with hybrids more suited to 30,000 to 35,000 plants per acre, number of rows around the ear and kernels per row, make a huge difference. He recently found two different hybrids in the same field, and discovered that one consistently put on 16 rows of kernels and one only put on 14, even in a favorable growing season like this one. Row number is highly genetic, he says. Environment influences it usually only if it is a stressful year.

The ears with more rows tended to be slightly shorter, however, with 40 kernels per row, still a good number. The ears with 14 rows tended to be a few kernels longer, at 42-44 kernels per row.

When he crunched the numbers in formula for estimating yield, he still came out with a 10 bushel advantage for the hybrid that put more rows of kernels around the ear. Exactly how much advantage depends upon precisely how many kernels finish per row.

Yields in fields with hybrid producing ears with 16 to 18 rows of kernels and 40 or more kernels per row could be very high, he notes. The final factor will be grain fill during this month, though it could be largely dependent on weather.

For more corn news, corn crop scouting information and corn diseases to watch for, follow Tom Bechman’s column, Corn Illustrated Weekly, published every Tuesday.


CORVALLIS, Ore. – If you grow corn in your home garden, then you might want to harvest fresh “baby” corn ears this summer.

Baby corn, those tiny ears of corn popular in Asian cooking and a favorite in salad bars across the United States, is largely imported from East Asia. It is usually processed and sold in cans or jars.

The miniature size of baby corn makes consumers think that it grows from dwarf corn plants. But the tiny ears of baby corn are simply immature ears from regular-sized plants, said Jim Myers, Oregon State University vegetable breeder.

Although specialty varieties are available for baby corn production, baby corn can be harvested from many common corn varieties, as well. All you need to do is harvest some of your garden sweet corn early. Field, regular, sugary enhanced or super sweet corn varieties work great for baby corn. You don’t need to buy the fancy stuff from the store.

But be aware: Sweeter varieties of corn do not produce sweeter baby corn, said Myers. Since baby corn ears are harvested before pollination and also before sugar has been stored in the kernels, baby corn is too underdeveloped to be sweet.

For baby corn, monitor the growth of your corn ears carefully. Corn grows so quickly, that timely harvest is crucial. In an extra day or two, the corn can grow larger than you might like for baby corn, giving a tougher and larger ear than might be good in a stir fry dish or salad.

To harvest baby corn at the perfect time takes practice. You might need to harvest a few at different stages each day for a few days to learn exactly when the baby corn is at the perfect stage for you. Start by harvesting ears where silk appears that day. Each ear may reach this stage at a different time on each plant, so you’ll have to watch your plants closely.

Baby corn ears are best harvested when they are 2 to 4 inches long and one-thirds to two-thirds inch in diameter, whether grown with a regular or close spacing pattern.

Refrigerate baby corn, with husks on, immediately after harvest if you don’t use it right away. Baby corn can be pickled or canned, or blanched and frozen.

A few seed companies offer special baby corn varieties, grown solely for baby corn. These varieties are just as big as regular corn plants, but may have more ears per plant. They are not dwarf corn plants. If baby corn varieties were allowed to mature, they would look like a typical medium-sized ear of field or sweet corn, said Myers.

It you want to grow a patch of corn specifically for baby corn, you can save space by planting corn seed much closer together than usual. Sow each seed about 4 inches apart in the row. Keep the row spacing to the normal 30 to 36 inches apart.

Baby corn has fewer pest problems than full-sized ears of corn. Corn earworms and cucumber beetles generally do their damage later, when the corn ear is filling out and maturing.

Home gardeners can harvest baby corn and mature sweet corn ears from the same plant, said Myers.

“They may want to harvest the lower ears for baby corn, then allow the top ear on a plant to mature for sweet corn,” he said.

Most any sweet corn variety will work well as baby corn. According to information from the University of Minnesota, starchy feed corn, with a tendency to grow multiple ears, also works well harvested as baby corn.

For more information, take a look at the Extension publication Baby Corn.

The Selective Science of Baby Corn


From little critters to tiny vegetables. For our food moment this weekend, we have some questions about baby corn, you know, the tiny little ears that show up amid the broccoli and bell pepper in your stir-fry. Because it’s not widely grown in the U.S., finding someone to talk about the mini crop proved a bit more difficult than we expected.

Not even the good people at the Department of Agriculture in Nebraska, the Corn Husker State, could give us what we were looking for. Then we found Jim Myers, a professor of vegetable breeding and genetics at Oregon State University. He joins us now from his home in Corvallis, Oregon. Welcome to the program, sir.

Professor JIM MYERS (Vegetable Breeding and Genetics, Oregon State University): Well, thank you.

ELLIOTT: So Doctor Myers, please solve this mystery for us. Is this a Lilliputian variety of corn or is it really just baby corn?

Professor MYERS: Baby corn comes from regular corn. It can come from any number of different kinds of varieties, but it’s just picked at a much earlier stage, before it’s even been fertilized. With corn, what you’re eating with a corncob is actually the female part of the plant. There’s also a tassel which sheds pollen, and that pollen has to drift onto the silks and then fertilize those individual kernels for them to go ahead and develop, and you’re harvesting this corn before that fertilization process has actually taken place. It’s like going out and picking an apple before that apple blossom has even opened up.

ELLIOTT: How is it harvested?

Professor MYERS: It’s taken just by hand. People come into a field one or two days after the silks emerge and just strip out the ears.

ELLIOTT: Now, wouldn’t it be more profitable to wait until the corn is fully grown to harvest it?

Professor MYERS: Certainly in terms of nutrition and what you get to eat. You get much more if you wait till it’s mature. But baby corn itself is very profitable. It’s very high-priced.

ELLIOTT: Now, in our research we discovered that most of the baby corn that we eat here in the U.S. is actually imported. Where is it coming from?

Professor MYERS: Thailand is a major area of production. That’s the main one I know about.

ELLIOTT: And why isn’t baby corn grown so much in the United States?

Professor MYERS: Maybe the biggest impediment is all the labor involved. It’s a very labor-intensive crop. We have mechanical harvests for full-sized ears but not for baby corn.

ELLIOTT: Let’s talk about the taste of this baby corn. I don’t find it to be terribly bitter like you would some vegetables that are not fully ripened yet, but it doesn’t have much taste at all, really.

Professor MYERS: No, it’s got a typical corny taste, but there’s no sugar that’s been deposited in the kernels yet, so it doesn’t have any of the sweetness that we normally associate with something like sweet corn, or the starchiness.

ELLIOTT: So mostly it’s just kind of cute but not much nutrition or taste there.

Professor MYERS: Right. It’s kind of cute. It adds some interest to the plate of food that you add it to.

ELLIOTT: Now why is it that we can’t find this fresh, you know, in the produce section of the grocery store with little baby husks and baby corn silk poking up?

Professor MYERS: Well, it, you can find it in farmers’ markets.


Professor MYERS: Not in your typical grocery store. Baby corn is typically sold in the husk, and my guess is that in a grocery store situation, there’s probably more labor than your typical consumer wants to go to. It’s much easier to buy a little jar of canned baby corn or something like that than…

ELLIOTT: Than to try to husk a dozen little baby corns.

Professor MYERS: Right. Yes.

ELLIOTT: Jim Myers is a professor of vegetable breeding and genetics at Oregon State University. Thank you for your help, sir.

Professor MYERS: Well, thank you very much.

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What is baby corn really?

It turns out that baby corn is indeed, just exactly what it sounds like — baby corn. “Baby corn comes from regular corn,” Jim Myers, a professor of vegetable breeding and genetics at Oregon State University told NPR. “It can come from any number of different kinds of varieties, but it’s just picked at a much earlier stage, before it’s even been fertilized.”

The mystery behind baby corn may not be particularly earth-shattering, but unlike a lot of the adult-sized corn we eat in the United States, most of our baby corn supply is imported from overseas. According to Myers, a lot of baby corn comes from Thailand simply because harvesting it is so labor-intensive. American farmers typically use huge mechanical machines to harvest mature corn, but baby corn must be delicately harvested by hand… because it’s just an itty-bitty baby.

Harvesting baby corn simply involves stripping the ears of corn from the stalk one or two days after the silks emerge. We typically see it in jars and cans at the grocery store because stores assume that most shoppers don’t want to bother with removing the silk threads from teeny tiny ears of corn. As Taste points out, the crunchiness of baby corn makes it ideal for salads and stir-fry dishes, but because it’s young, it lacks much nutritional value.

What this little corn lacks in nutritional value, though, it clearly makes up for in sheer cuteness.

Maize biology

Each maize plant is monoecious: that is, it has separate female and male parts.
The ear, or cob, is the female part of the plant; the silks near the top of the ear are really elongated stigmas, each growing from an egg on the cob.
The tassel at the top of the plant are the male part of the plant that produce the pollen. The tiny pollen grains are carried by wind to the silks, either of the same plant or a different plant, where they travel down inside the silk to fertilize an egg, which will become a kernel. In maize, the kernels are seeds, each containing a single embryo. These are the parts you would plant to grow new maize plants.

The kernels (there can be around 400 – 1000 on each ear) are attached to a cob and enclosed by layers of leaves. In the early part of the season, the whole cob could be eaten in its entirety (as with baby corn) but later in the season the kernels become harder and are best eaten cooked. Without human intervention (harvesting and cooking!), the cob would eventually fall to the ground and a new maize plant would sprout from each kernel. However, since the types of maize we currently eat have been selected to have large kernels and a big cob, the kernels would fall in a heap and not have room to grow into a healthy plant (see section on What is domestication?). When farmers grow maize, they plant kernels in rows, leaving enough space for each kernel to develop into a large, healthy plant. Maize can only grow with human help, since it has been modified from its ancestral form by domestication.

Why Corn Is a Fruit

Ready for your mind to be blown? According to Encyclopedia Britannica, “Fruit, in its strict botanical sense, the fleshy or dry ripened ovary of a plant, enclosing the seed or seeds.”

If you think about a typical fruit, like apples, that makes sense. The apple flesh surrounds a core containing seeds. But in corn’s case, each kernel is what’s called a caryopsis, basically a type of dry fruit where the ovary wall and the seed coat are fused into one layer.

Why Corn Is a Grain

The plants that produce these special fruit-seed combos all belong to the same family of cereal grasses: Poaceae. They include corn, wheat, rice, oats, and barley — i.e., grains. In fact, Merriam-Webster primarily defines grain as “a seed or fruit of a cereal grass; caryopsis.”

That’s why you might see popcorn described as a “whole-grain food.” You’re actually eating the whole kernel with all its original parts.

Why Corn Is a Vegetable (Kinda)

Jodi PudgeGetty Images

When Mom put an ear of corn on your plate and said “eat your veggies,” she wasn’t totally wrong. For all intents and purposes, most of us define it as such. Look for corn in the grocery store, and you’ll find it in the veggie section. The most recent USDA Dietary Guidelines for Americans lists corn as both a starchy vegetable and grain.


Even the Whole Grains Council is on board with a hybrid definition. “Fresh corn is usually classified as a vegetable, and dried corn (including popcorn) as a grain,” it states.

So while botanically speaking corn is not a vegetable, you can still get away with calling it one.

“Categories aside, corn is a plant-based source of phytonutrients, says Jaclyn London, MS, RD, CDN, Nutrition Director at the Good Housekeeping Institute. “You’ll get a higher amount of dietary carbohydrates per serving than you do of non-starchy veggies like leafy greens, broccoli, carrots, and eggplant, which have fewer calories.”

Her advice: Cut back on the butter-soaked movie theater popcorn and corn syrup-sweetened drinks and use corn in its more nutritious forms, like on the cob, in a salad, or as a replacement for white rice.

Caroline Picard Health Editor Caroline is the Health Editor at GoodHousekeeping.com covering nutrition, fitness, wellness, and other lifestyle news.

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