Corn is the biggest U.S. grain crop and you can grow it, too!


Fresh from the garden ears of sweet corn, heated, and then topped with butter, salt, and pepper, well, life just doesn’t get much better than that! Now, we are not talking about the corn used to feed livestock. That brand is called grain corn. Sadly, I wasn’t particularly happy with my Indian corn crop experience, either. It may have historical merit, but the kernels were tough and very starchy. Call me spoiled, but I prefer my corn with fat, sugar-filled kernels that  burst on my tongue with every bite.

History of corn

For anyone who has had the opportunity to explore Mitchell, South Dakota, you know there’s a lot to be said for corn. Corn, or maize, was domesticated by people in what is now Mexico nearly 10,000 years ago. Early corn plants only grew 1-inch long cobs, and only one cob per plant. Selective breeding brought us to cobs of several inches in length and plants capable of producing multiple cobs on each plant. One of the three most genetically modified crops, nearly 90% of the U.S. corn harvest is of GMO corn. In addition to being eaten from the ear, or as grits or meal, corn (Zea mays) is also used as a sweetener (high fructose corn syrup), biofuel, and to make plastics, fabrics, adhesives, and liquor. There are six types of naturally occurring corn (and 142 GMO types, as of 2015). Those six types are dent corn, pod corn, flour corn, flint corn, popcorn, and our beloved sweet corn.


How corn grows

Being a member of the grass family (Poaceae or Gramineae), corn is cousin to bamboo, rice, and your lawn. Corn grows a hollow stem that is wrapped with leaf blades. Each corn plant produces both female and male flowers, but they are not self-pollinating. This is called monoecious. These flowers both start out bisexual (referred to as ‘perfect’ in the world of botany), and then develop into one gender or the other.


Corn kernels are actually female inflorescences, or flower clusters, that turn into fruit. These fruits are protected by tightly wrapped leaves that we call husks. At the top of each stem (or cob) is a male inflorescence (tassel) that releases pollen onto the wind. The silks we work so hard to remove are actually elongated stigmas from the female flower. There is an ovary at the end of each silk thread that must be pollinated for fertilization to occur, allowing a kernel to develop. Since pollen is carried on the wind, corn must be planted in blocks, rather than rows. 


How to grow corn

Corn needs lots of nutrients in the soil, so be sure to prepare the beds ahead of time with plenty of aged compost. Corn does not transplant very well, so wait a couple of weeks after your last frost date before planting. Seeds should be planted one inch deep and 4 to 6 inches apart. Soil needs to be at least 60 degrees for germination to occur. Once your corn seedlings emerge, thin them to 8 to 12 inches apart. Corn plants have very shallow roots, so proper irrigation is important. In the heat of summer, your corn plants may need an average of 5 gallons of water per square yard each week. Since each microclimate is different, you will have to make your own adjustments. Just keep in mind that insufficient irrigation can reduce the number of silks that emerge and that means less developed kernels on your ears of corn. One way to give your corn seedlings an extra boost of nitrogen is to use the Three Sisters Method and plant corn with beans and squash. The beans ‘fix’ atmospheric nitrogen, making it available to nearby plants, and the squash produce large leaves that shade the soil.


Corn pests and diseases

We are not alone in our love of corn. An old saying tells us, “One for the blackbird, one for the crow, one for the soil, and one to grow.” You may or may not be able to scare away the crows (and chickens) with scarecrows (I use my dogs), but nothing can stop a determined raccoon. It is the smaller pests, however, that will probably cause you the most problems. These generalists include: armyworms, aphids, spider mites, thrips, wireworms, cutworms, flea beetles, cucumber beetles, and grasshoppers. Corn-specific pests you might see are corn leafhoppers, corn leafminers, seedcorn maggots, and corn earworms. Corn is also subject to fungal and bacterial diseases, such as smut, soft rot, fusarium root and ear rot, maize dwarf mosaic, pythium stalk rot, seed rot, and damping-off disease. 


Harvesting corn

Sweet corn loses its sweetness soon after harvesting, so pick it as you will be eating it. Corn is ready for harvest when the tassels turn brown. If your harvest is bigger than you can eat, corn freezes well.


If you have a patch of ground, give corn a try this year!

The Three Sisters of Native American agriculture are corn, beans, and squash.


These ‘sustainers of life’ have a rich history of folklore, spirituality, and early agriculture. They also make sense in the garden. The Three Sisters Method of growing is an example of drought tolerant companion planting that has withstood the test of time.


The Three Sisters Method was believed to have been started by the Iroquois, or the Haudenosaunee, found in the northeast region of the Great Lakes region. This collection of five nations spoke similar languages and shared agricultural information. Native Americans relied heavily on winter squash, such as pumpkins, corn (maize), and climbing (or pole) beans for both food and trade goods for several hundred years. This successful growing method spread west and south to what would become Utah, Colorado, Arizona and Mesoamerica.


Benefits of the Three Sisters Method

Planting these three sisters together allows them to benefit each other in several ways:

• corn stalks provide a climbing structure for the beans
• young beans add nitrogen to the soil
• wide prickly leaves of the squash shade the ground, stabilizing temperature, reducing evaporation and competition from weeds, and deterring pests

In some areas, a fourth plant was added to the mix. This was usually a flowering plant used to attract pollinators, such as honey bees, to increase yield. Just as the three plants benefit each other as they grow, eating them together provides fatty acids and the eight essential amino acids needed to form complete proteins.

Planting by the Three Sisters Method

Rather than planting in rows, the Three Sisters Methods calls for flat-topped mounds, 12” high and 20” wide. Several corn seeds would be planted in each mound. In some areas, rotten fish or eels would be added at the same time, to act as fertilizer. Some areas planted all three types of seeds at the same time. Others would wait until the corn was 6” tall before adding squash and beans. Seeds would be alternately planted around the corn. Two types of beans were used: common beans (Phaseolus vulgaris) and tepary beans (Phaseolus acutifolius), which are more drought tolerant.


You can create your own Three Sisters garden design using the same companion planting concepts. Since corn has higher pollination rates when planted in blocks, rather than rows, you can set aside an area of the yard, or a raised bed, as your very own Three Sisters garden.


The corn will grow up, the beans will climb the corn and add nitrogen to the soil, while the squash protects the ground with its wide leaves. Come autumn, your family will be able to enjoy a high protein meal of beans and corn with a side order of baked or steamed squash, with very little effort on your part.


Give it a try this growing season and see how well it works for you!