Sweet Corn

Ear of sweet corn

Photo by Doug Wilson, USDA/ARS

Sweet corn is a favorite among home gardeners. As long as the space is available, it's not not difficult to grow.

Corn is a New World native crop, with archaeological evidence suggesting that it was first domesticated in Mexico. This crop was the basis of the Mayan, Incan, and Aztec civilizations, and by the time European explorers came to the new world in the 1500s, corn had become a staple for the native people.

Characteristics

Corn comes in a variety of colors and sugar contents. Look for sugary enhanced (or "se") varieties, with firm and sweet kernels, or the super sweet (or "sh2") varieties, with tender and very sweet kernels. Some varieties of white and yellow corn that perform well in Florida are 'Silver Queen' (white), 'How Sweet It Is' (white), 'Sweet Ice' (white), 'Sweet Riser' (yellow), and 'Early Sunglow' (yellow).

Planting and Care

Corn should be started from seed and planted in an area where it will receive at least 6-8 hours of sun each day. Make sure you plant only one type of corn to avoid cross pollination of different varieties.

For best results, plant two to three rows of corn with each row 24 – 36 inches apart. Seeds should be planted 1 – 2 inches deep with individual plants spaced 12 – 18 inches apart. Avoid planting seeds in poorly drained soil as this will promote seed rot.

Corn plants can reach 6 - 8 feet or more in height; keep this in mind as you plan out where to plant your corn. Make sure you take into account the shadow that mature corn plants will cast over other plants in your garden.

Water your corn in the mornings, giving the foliage time to dry before dark. Critical periods for watering are during pollination and ear filling. About 1 inch of water is required per week for your corn to develop normally. Be sure to water so that the soil is moist to about 6 inches deep, as light sprinklings of water will encourage shallow rooting.

Male and female parts of corn

Flowers from corn. Male flower (tassel) is on the left; note pollen grains on the anthers. Female flower "silks" (stigma) are on the right. Photo by E. Thralls. UF/IFAS, EDIS.

Pollination

Corn production depends on pollination; however, in a garden with only a few rows of corn, relying on the wind to pollinate your plants may not provide you with a reliable harvest or may result in cobs with large gaps between the kernels. Don't worry though; you can easily pollinate your corn by hand.

Each plant has male and female flowers. The male flowers, or "tassels," are branched floral structures at the top of the stalk. The female part of the corn is the ears, the part you eat, and the "silk" are the female flowers. You will find one to four ears per stalk, depending on the variety, located on the stalk just above the leaves at the nodes.

In order for your corn to be pollinated, pollen grains from the tassels have to come into contact with the silks. There are two ways you can pollinate your corn by hand. One way is to cut an entire tassel off the plant and use it like a wand to shake the pollen onto the silks. You can also strip the tassel and deposit the pollen directly onto the silks. When pollinating the silks, make sure you are thorough to increase your chances of a bountiful harvest.

Harvesting

Sweet corn is ready to harvest when the kernels are filled and tightly packed, usually between 60 and 90 days after planting. They should be picked within a day or two, and eaten immediately for best flavor. With most sweet corn varieties, the majority of the ears will mature at the same time. In order to keep your garden supplying corn for a longer period of time, try staggering your plantings.

Sweet corn can be affected by various insects and diseases. Before trying to manage a pest problem, be sure to get it properly identified; your local county Extension office can help you do this.

With a little planning and care, you can have your own source of corn for your summer grilling and enjoyment.

Companion Planting

Corn is one of the crops at the heart of what is probably the best known historical example of companion planting, the "Three Sisters." The other two crops are beans and squash.

Corn requires a lot of nitrogen to grow well. Beans are "nitrogen fixing", meaning they can convert nitrogen from the air into a form usable by plants. While the nitrogen isn't immediately available to the corn, the decomposing roots of spent bean plants provide nitrogen to subsequent crops. The third sister, squash, is a low growing plant with broad spreading leaves. The spreading squash forms a shady mulch which can help reduce weed growth and hold in moisture. The prickly squash plants may also help deter raccoons. In turn, corn provides climbing beans, like pole beans, with tall support stalks, while the shade provided by the corn plants can potentially confuse a major squash pest, the adult squash borer.

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