Zea mays (Corn)

Corn (Zea mays) is a warm-season annual crop grown for its large ears of tasty kernels. Easy to grow, Corn is one of the world’s most popular cereal grains. Popcorn and Sweet Corn are dominant varieties, however, refined Corn products are also widely consumed, usually as ingredients in processed food.

• Corn is a cereal grain from the same family as wheat, rice, or barley (Poaceae), but it can be considered either a grain or a vegetable based on when it is harvested.
• Corn harvested when fully mature and dry is considered a grain. As an example, Popcorn is considered to be a whole grain.
• Fresh Corn (Corn on the cob, frozen Corn kernels) is harvested when it is soft and immature and considered a starchy vegetable.
• Corn was first cultivated in southern Mexico about 10,000 years ago from a wild species called teosinte. In the 16th century, Columbus brought it to Europe.
• Today, Corn has become a staple food worldwide, with the total production of Corn surpassing that of wheat or rice.
• Corn is an essential element of the daily diet of animals and humans.
• Besides food and animal feed usage, there are more than 3,500 different uses for Corn. It is processed into many food and industrial products, including starch, sweeteners, corn oil, flour, cereals, beer, whiskey, syrups, and biofuels.
• Sweet Corn is especially popular with home gardeners because it tastes much better when harvested and eaten fresh from the garden.
• Typically yellow, Corn also comes also in various colors, such as blue, red, orange, purple, white, and black.
• According to the USDA, it is important to farm Corn as it helps reduce global warming and greenhouse gas effect. One acre of Corn eliminates about 8 tons of carbon dioxide from the air just in one growing season.

Main Types of Corn

Sweet Corn

• Sweet Corn is the major type of Corn eaten by people and can be found in your grocery store.
• It is harvested early when the kernels are still immature and are creamy, soft, and flavorful.
• Sweet Corn is super sweet because it contains more natural sugars than the other types of Corn.
• Sweet Corn cultivars are classified into 3 groups: normal sugary (traditional corn flavor), sugar enhanced (increased tenderness and sweetness), and supersweet (almost candy-sweet).
• Almost 50% of the sugar can be changed to starch only 24 hours after Sweet Corn is harvested, so it is best to eat it fresh to enjoy its full sweetness.
• Sweet Corn is primarily eaten on the cob, but it can be canned or frozen. It will never pop.
• Sweet Corn always displays an even number of rows and comes in yellow, white, or a combination of the two colors.
• This is the one cereal crop that home gardeners are likely to grow.

Field Corn or Dent Corn

• Field Corn is the most widely cultivated Corn in the United States.
• Field Corn is used primarily for livestock feed and is not eaten by humans. It is also used for fuel, in industrial products, or to make processed foods such as tortilla chips, grits, or corn syrup.
• Field corn is harvested later in the season when the plant has dried and the kernels are hard.
• It forms a dent, or dimple, on the top of each kernel when it starts drying out, thus the name Dent Corn.
• Either white or yellow, Field Corn contains more starch and less sugar than Sweet Corn.

Flint Corn or Indian Corn

• Flint Corn is similar to Field Corn. It has a hard outer shell and comes in many colors, including red, white, blue, black, and gold.
• It is grown mainly in Central and South America and used primarily for fall decorations.

Popcorn

• Popcorn is harvested when the kernels are hard and dry.
• The kernels have hard, moisture-resistant outer shells that protect a dense pocket of soft starch. When heated, the moisture inside the kernel gives off steam and builds up enough pressure to explode up to 50 times its original size.
• Some varieties form a snowflake, butterfly, or mushroom shape when popped.
• Popped Popcorn has a nutty flavor and crunchy texture.
• Popcorn kernels can be white, yellow, red, or black and vary from small to large.
• Other types of dried Corn may pop to some degree when heated, but Popcorn is unique in its taste and the most explosive.
• Popcorn is a good source of fiber and manganese, and it also contains protein and zinc, as well as magnesium and phosphorus. Popcorn is considered a low-calorie, low-glycemic food.
• Popcorn is one of the oldest forms of Corn: remains of ancient popped Popcorn were found in Peru and date back nearly 6,700 years ago!

Baby Corn

• Baby Corn is a specialty crop widely cultivated and consumed in Asia. It is grown from regular Sweet and Field Corn varieties.
• Baby Corn is harvested young before fertilization when the cobs are only 2-4 in. long (5-10 cm). The miniature cobs are covered in tiny creamy to pale yellow kernels arranged in straight rows.
• Baby Corn is entirely edible. Its flavor is mild, subtly sweet, and earthy. It is tender and has not developed high starch or sugar levels.
• Baby corn is available year-round in canned form. When fresh, it has a peak season in the spring and summer.
• Baby corn adds crunch, texture, and visual interest to dishes. It can be added to salads, served with dips as an appetizer, or stir-fried with other vegetables as a fresh entrée.

Corn Health Benefits

• While Corn makes a flavorful addition to salads and various dishes, it can also provide some health benefits.
• Corn is naturally gluten-free and a member of the whole grain family.
• Whole grain absorption is associated with a lower risk of heart disease, colorectal cancer, type 2 diabetes, and obesity.
• Corn contains many vitamins and minerals that help several body processes and functions. Popcorn is rich in minerals, while Sweet Corn is higher in many vitamins.
• The nutritional content is, however, best preserved when it is eaten whole or as Popcorn. Steaming, boiling, or roasting reduces the nutritional value.
• Corn provides higher levels of antioxidants than many other cereal grains. It is especially rich in carotenoids, zeaxanthin and lutein, which are important for eye health and help prevent cataracts.
• When it comes to nutrients, color matters. Colorful Corn (other than yellow) has been found to include more antioxidants.
• Yellow Corn may be a rich source of beta-carotene, which forms vitamin A and is essential for maintaining good vision and skin.
• Corn also contains smaller amounts of vitamins B, E, and K and minerals like magnesium and potassium.
• Potassium supports healthy blood pressure, heart function, and muscle contractions.
• Magnesium may decrease many chronic illness risks, such as heart disease.
• Popcorn and Sweet Corn are decent phosphorus sources that play a key role in the growth and maintenance of body tissues.
• Sweet Corn is a good source of soluble fiber that helps you feel fuller and plays a role in preventing constipation.
• A word of caution:
• Corn is a starchy vegetable. It is mainly composed of carbs and contains small amounts of sugar that can raise your blood sugar levels.
• Although rare, some people may develop an allergy to Corn or Corn protein.

Growing Corn

• Corn grows up to 4-10 ft. tall (120-300 cm) and 1-3 ft. wide (30-90 cm), depending on the variety.
• Corn performs best in organically rich, acidic to neutral (pH ranging from 5.5 to 7.0), moist, but well-drained soils in full sun (at least 6-8 hours of direct sunlight per day) in a sheltered location.
• Before planting, add well-rotted organic matter or compost and work it into the soil.
• Keep the soil evenly moist but not soggy. Corn has shallow roots and can become stressed by drought. Water the ground, not the plant, or pollination could suffer.
• Depending on the variety, Corn takes 60-100 days to harvest.
• Corn is a warm-weather crop that is sensitive to frost and should not be planted until the soil warms up to 60°F (15°C) or 75°F (24°C) for supersweet varieties. Seed planted in cooler soil is prone to many problems, including poor germination.
• To help speed soil warming, cover the soil with clear plastic at least 2 weeks before you want to plant.
• For a non-stop supply of Corn throughout the summer, try sowing early, mid-season, and late cultivars at the same time or sowing one early cultivar another two times, three weeks apart.
• Corn is pollinated by the wind. Each Corn silk is attached to a kernel of Corn, and each must be pollinated for that kernel to grow. As a result, it is best to plant Corn in blocks (all the same variety) rather than long single rows to ensure good pollination. A minimum of 15 or more plants is usually necessary. To help pollination, you may want to gently shake the stalks of the plants every few days (in the morning) until the tassels are no longer viable.
• Sow seeds 1½ to 2 in. deep (3-5 cm) and 2-4 in. apart (5-10 cm). Water thoroughly at planting time.
• After planting, use a row cover for about a month to boost the seedlings.
• When seedlings are close to 4 in. tall (10 cm), thin them to 12-18 in. apart (30-45 cm) for short varieties and 18-24 in. apart (45-60 cm) for tall varieties.
• Corn is a heavy feeder and must have ample nitrogen. Side-dress plants with a high-nitrogen fertilizer when Corn is 8 in. tall (20 cm) and again when it is 18 in. tall (45 cm).
• Rotate crops: Do not plant Corn where it has grown in the past 2 years to prevent issues.
• Mulch to retain moisture, keep the soil warm, and control weeds.
• Harvest your Corn when the ears reach maturity, the corn silk turns brown, and the cob becomes more rounded towards the bottom. Kernels that are ready for eating have a milky white interior. Try shucking a small section of the corn ear and piercing a kernel to check.
• If the Corn looks ready, stick it in a pot of boiling water or on your grill as quickly as possible. The fresher the Corn, the sweeter its taste will be.
• If you want to dry your Corn for seed or storage, leave the cobs of Corn on the stalk for 6 to 8 more weeks.
• After harvest, cut or mow stalks and let them dry. Then turn them under or collect and compost them. Destroy any diseased or infested material.
• Corn is susceptible to a few pests. Keep an eye out for birds, badgers, aphids, armyworms, corn borers, corn earworms, grasshoppers, Japanese beetles, slugs, snails, mice, spider mites, stink bugs, and wireworms.
• Corn is susceptible to diseases, including corn leaf blight, corn smut, and corn viruses.

Best and Worst Companion Plants for Corn

• Excellent companion plants for Corn are beans, borage, cantaloupe, crowder peas, dill, eggplants, geranium, lettuce, lovage, marigolds, melon, mint, muskmelon, nasturtium, peas, potatoes, pumpkin, soybeans, sunflower, summer squash, thyme, tomatillo, watermelon, winter squash.
• A good example of companion planting is The Three Sisters Garden. Practiced by Native Americans thousands of years ago, this garden includes Corn, beans, and squash. The tall Corn provides shade for the lower squash but also stops the squash vine borer beetle. Corn also provides support for the bean plants to climb up. The beans enrich the soil with nutrients for both Corn and squash. And the large leaves of the squash vines create a protective mulch that helps retain moisture while suppressing weeds. Another added benefit is the prickly vines of the squash deter the raccoons from stripping the corncobs.
• Borage flowers are pretty and not only attract beneficial insects but can deter pests from your Corn. As a bonus, they are edible.
• Lovage improves the flavor and vigor of most plants and offers a good habitat for ground beetles.
• Similarly, Marjoram is a friend to all plants and helps improve growth and flavor.
• Eggplants are good companion plants because they deter raccoons from eating the Corn, and in return, the Corn protects the eggplant from a virus that causes wilt.
• Sunflowers attract hoverflies, lacewings, parasitic wasps, tachinid flies, bees, and masses of goldfinches. They also attract aphids away from the Corn onto their stalks, where minor damage can be done.
• Soybeans are good companions to Corn as they add nitrogen to the soil and protect Corn against chinch bugs and Japanese beetles.
• Yarrow is a good companion for vegetables, in particular Corn.
• Keeping dill close to Corn attracts beneficial insect predators, which will help pollinate Corn and keep other pest levels down.
• Peas help Corn by restoring to the soil the nitrogen used up by the Corn.
• Geraniums have also been reputed to repel cabbageworms and corn earworms.
• Melons, squash, and pumpkins like the shade provided by Corn. In turn, they benefit the Corn, protecting it from raccoons, which dislike traveling through the thick vines.
• Cucumbers are offensive to raccoons, so they are a good plant with Corn. And Corn protects the cucumber against the virus that causes wilt.
• Marigolds are among the most popular companion plants because they repel a wide range of pests, including aphids and Japanese beetles.
• Nasturtiums are pretty edible flowers that attract aphids away from vegetable crops.
• Thyme is an aromatic herb that can repel corn earworms.
• Do not plant Corn near broccoli, brussels sprouts, cabbage, cauliflower, kale, kohlrabi, tomatoes, celery, or fennel.
• Corn and crops in the cabbage family are heavy feeders. If planted together, they will compete for nutrients in the soil. In addition, the Corn would provide too much shade for these sun-loving plants.
• Do not plant tomatoes close to Corn, as the tomato fruitworm is very similar to the corn earworm. They would attract more pests if planted together, and the damage would be more extensive.
• Celery has few insect enemies but should not be grown near Corn, as the corn worms will infest it.
• Fennel is one of the few plants that has mostly bad companions. Most plants dislike fennel, and it should be planted well away from the vegetable garden. Fennel inhibits the growth of any nearby plant, including Corn.