How Long Does It Take to Grow Corn?

Sweet corn varieties take 60-90 days to grow mature cobs ready to harvest. Ornamental and popcorn varieties take longer and will mature in 90-120 days.

Sweet corn is “milk stage harvested” and the window for picking is very important. All other types of corn are dry harvested, left in the field to dry out most of the way.

Can You Hear Corn Grow?

Yes you can. In this time lapse video done by Nebraska University, the Cornhuskers, you can actually hear the corn growing. At the beginning of the video it explains that think the noise is the plant breaking and rebuilding itself.

How Long Does It Take Corn to Sprout?

If corn seeds are planted directly in the soil they will sprout in anywhere from 4 days to 3 weeks. Corn seed will sprout faster with warm weather and slower with cool weather. The longer the seed sits in the dirt without sprouting the higher the likelihood of needing to replant.

Checking the soil temperature is the best way to know when to plant. Before planting seed corn, soil temperatures should average 60 degrees or above.

Click Image to Shop

A cheap soil temperature gauge looks just like a meat thermometer but reads down to lower temperatures.

Measure the temperature between 9-11 AM to get an average soil temperature, after the night chill has worn off but before the afternoon sun heats it up. Put the whole stem of the thermometer into the dirt and let it sit for 5 minutes. If it reads 60 or above you’re good for takeoff.

It will take 3 or 4 days with air temperatures above 70 degrees for the soil temperature to reach 60 degrees. Break the soil up with a shovel or pitchfork in early spring to make sure the soil isn’t compacted, break up any frozen soil, and to let it dry out.

Here’s a great article by Washington State University that goes in depth on corn seed germination.

Does Corn Grow More at Night?

Yes it does. The best that I can understand is the photosynthesis process allows the plant to build up starch and other resources that are used during the night by the plant to grow. It is also on a circadian rhythm. Here’s a scientific article that explains it better.

How Fast Does Corn Grow?

In the first four weeks corn will grow to 24″ tall, at a rate of about 0.8 inches a day. Corn grows fastest from knee high until it begins to tassel. This is around a 5 week window where corn will grow about 2.5 inches a day. Corn will tassel sometime around week 9 or 10 and won’t grow much taller after that.

In reality corn grows more in spurts. Hot weather with enough watering will make corn grow faster than colder weather. If plants don’t get enough water during hot spells they’ll become stressed and stop growing.

In a Tale of the Week in the Fairfax Standard printed in October 28, 1909 a man recorded his corn growing at an average rate of 5 1/2 inches a day from July 8 to July 15. The record stated the weather was hot during this time.

In Michigan where I live “knee high by the 4th of July” is corn that’s on schedule. Corn is started in the middle of May so it sprouts by June 4 giving it a month to reach knee high, about 24″. That’s 24″ in a month and 0.8″ a day.

Average corn height is 9′ or 108″ tall. Corn is harvested in Michigan starting 10/3 but field corn tassels about 70 days after sprouting. If corn sprouted on June 4 it would tassel around August 14. So 70 days for 108″ of growth averages out to about 1″ a day. This comes out to about 1.5″ a day over the corn plants life cycle.

Pause the below video at 25 seconds in for a graph that shows how much corn grows. Here’s a different graph of the corn growth stages from Kansas State University.

Is it Hard to Grow Corn?

Corn is very easy to grow. It’s a member of the grass family! Most people will say it’s easy to grow but you need a good amount of space. They say that corn is wind pollinated and if you don’t have a large enough block of corn the corn won’t get pollinated. Not true, just hand pollinate.

This is true enough, 97% of corn in a field is pollinated by neighboring corn but if you hand pollinate, very simple to do, you can have only one corn plant and be just fine.

Here’s an article that explains corn pollination. Basically, the tassels on top are the male flower and the silks coming out of the ear are the female flower. Each piece of silk can become a kernel if pollinated by a piece of pollen from a tassel.

If you did only have one corn plant you could expect it to have 2-4 ears instead of the 1 ear they usually get in fields. That’s because corn plants are spaced so tightly in the fields. Farmers get a better overall yield that way but for a home gardener giving the corn plenty of space will result in more ears of corn.

If you ever walk around a corn field you’ll notice that corn plants on the edge of the field tend to have more ears than those in the middle of rows. This is because the extra space gives them more access to sun, water, and nutrients.

Types of Corn & Dry Harvesting Corn

There are six types of corn: dent/field, sweet corn, popcorn, flint corn, flour corn, and pod corn. Here is an article about the five different types of corn.

Popcorn varieties and flint corn varieties (also known as indian corn) are the only kinds of corn with a kernel structure that will make popcorn. Some ornamental corn is flint corn and others are not.

Here are two beautiful ornamental corns, Glass Gem and Earth Tones. Glass Gem is a flint corn that will make popcorn and Earth Tones is a dent corn that won’t. It’s easy to tell because the kernel literally has dents in the top of it when the moisture in the kernel drys out. That’s how it gets its name.

Here’s a cool map of the US that lists each stage average start and end date for corn harvesting.

If the corn being grown is not sweet corn it’s harvested using the dry harvest method. That is leave it in the field until it turns brown and dries. Farmers can’t leave it in the field until it dries completely though and will harvest when it has about a 25% moisture content.

To sell it to the granary they need the moisture content to be 15% or less so they will have a grain dryer they use or sell it to the granary who will dock their pay because they will have to use their grain dryers to get the moisture content down to 15%.

Corn with a moisture content above 15% will have problems in storage with mold. To see more in depth about the difference between milk stage harvesting vs dry harvesting and when farmers harvest corn check out this article.

Please comment below with any thoughts, comments, questions, or experiences with how long it takes to grow corn!

Leave a Comment

Your email address will not be published.

Scroll to Top