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A kernel of truth about corn

For most of us, corn makes up a large part of our diet, sometimes intentionally by adding sweet corn on the cob as a side dish to a meal, and other times as an ingredient in manufactured food and drinks. It is an important crop globally and is grown everywhere in the world except Antarctica. 

Corn, as we know it, is not something you will find growing in the wild; it has been selectively bred and modified by humans for centuries to suit our needs. It started out as a wild grass called teosinte. It then became domesticated in Southern Mexico between 7,000 to 10,000 years ago. In ancient times, the ears were only about the size of a thumb. 

Corn, also known as maize, is said to have been grown by the Native Americans using the Three Sisters method, alongside beans and squash. They supported the growth of each other with the corn providing a structure for the beans to grow up, the beans provided nitrogen to the soil through its nitrogen fixing nodules on its roots, and the squash provided a mulch-like environment to help retain moisture and keep weeds down. Also as a harvest, they provide a balanced diet of proteins, carbohydrates and vegetable fats. 

The Native Americans taught the early European arrivals how to grow corn and Christopher Columbus took the seed back to Europe, along with many other new vegetable varieties. It is now a well-established staple food across the world to the point that more corn is now grown than wheat or rice. It was quite labour intensive to grow prior to the invention of the first mechanical harvester back in 1930.

Surprisingly, corn is generally quite uniform with an average ear possessing 800 kernels laid-out in an even amount of rows, with most ears having 16 rows. An ear is actually part of the flower and an individual kernel is a seed; corn is a fascinating plant! 

Corn kernels

Corn has been developed into six groups with different specialisations:


Often called field corn, dent has a really thick outer skin making it unsuitable for eating as you would normal sweetcorn. It has a soft starchy centre though making it ideal for food manufacturing and animal fodder.


This variety has a very hard kernel coating that is ‘ as hard as flint’ but a soft starch interior (not as soft as Dent corn though). Thanks to its low water content, it can cope with freezing temperatures. It is mainly used in food manufacturing processes but is also a popular material for ornamental North American Thanksgiving decorations and can also be used for popcorn.


Flour corn has a thin coating and a soft starchy centre so is perfect to be used to make flour. Corn flour is an indispensable ingredient in many recipes. 


Pod corn is probably the least known member of the corn family. This is a mutant that has leaves around each kernel and doesn’t have much use other than for ornamental purposes. 


Best left to dry on the plant, this is a really fun crop to grow. The kernels are hard but its interior is at a moisture level of 14 to 20% which turns to steam when heated and causes the kernel to explode to 20 to 50 times its original size. The result is the ever-popular much-loved popcorn. Apparently people have been popping corn for thousands of years.


For the home gardener, sweetcorn is the most interesting variety to grow, along with popcorn. This crop derives from a mutation that is responsible for turning sugars into starch, which is the reason why other corn varieties are left to dry on the plant whilst sweetcorn is eaten fresh in its immature “milk” stage which happens to be when it is at its sweetest. 

On the negative side, it does not store as well as other corns so needs to be eaten or processed quickly before the sugars turn to starch. Freshly harvested corn will lose approximately 40% of its sugar through converting to starch when stored for as little as 6 hours at room temperature so it makes perfect sense to grow it at home. 

Sweetcorn is a great addition to any diet as it is a rich source of vitamin A, vitamin B, vitamin E and is high in fibre. Note that it isn’t recommended to add salt to corn during cooking as it can make it tough but a dash before eating it, with or without a little bit of butter, is always a treat. 

Corn harvest