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In this Aug. 27, 2013 photo, these ears of sweet-tasting, bi-color corn were grown from seed in containers inside a hobby greenhouse near Langley, Wash. The Burpee's "On Deck" corn matured in a little more than two months. (AP Photo/Dean Fosdick)
(Dean Fosdick via AP)
One of life's great treats is biting into corn that was cooked just minutes after it was harvested from your home garden. If you've never had the experience of eating fresh sweet corn right out of your yard, now is the time to plant it. Sweet corn is not one of the more commonly planted home garden vegetables, and there are reasons for this.
Although it rarely grows as high as an elephant's eye, corn plants are fairly large, and they occupy a substantial amount of space in the garden. As a result, many vegetable gardeners don't plant corn, especially if they have a small garden.
Each plant produces about two ears of corn, so overall production in the space is not as high as it would be for other popular vegetables, such as tomatoes, squash, snap beans or trellised cucumbers. But if you have the space, growing sweet corn is not that much of a challenge, and the results are delicious.
Types to grow
Many early summer vegetables produce over a period of weeks or even months. Corn, on the other hand, is harvested over a relatively short period of time as all of the ears ripen at about the same time. You can get around this by planting cultivars that ripen at different times.
Recommended sweet corn cultivars grouped by how long to harvest include:
Early-maturing: Seneca Horizon
Mid-season: Bonanza, Merit and Funks Sweet G90 (bi-color)
Late-maturing: Silver Queen (white), NK199, Iochief (AAS), Gold Queen and Golden Cross Bantam.
Or, you can plant the same cultivar in succession. Plant seeds in one area and then plant seeds in another area two or three weeks later.
There also are extra sweet corn cultivars. They contain more sugar than normal sweet corn and are able to hold their sugar levels longer after harvest. Based on the genetics involved, they are grouped into two categories: supersweet and sugary enhanced. Recommended supersweet types (which must be isolated from cross pollination with ordinary sweet corn or sugary enhanced) include How Sweet It Is (AAS), Honey-N-Pearl (AAS), XTender 378, 372, 270 BC, Passion, Accelerator, Summer Sweet #8101W, Summer Sweet #7210Y, #8102 BC, Pegasus and Ice Queen.
Recommended sugary enhanced types include Honey Select (AAS), Avalon, Miracle, Argent, Incredible, Bodacious, Precious Gem BC, Ambrosia BC, Sweet Chorus BC, Temptation BC, White Out, Lancelot BC, Silver King and Sweet Ice. (AAS is All-America Selection Winner.)
Planting
Planting corn early -- now through mid-April -- reduces problems with corn earworms, the leading insect pest of corn in the home garden. When planted this month, corn typically does not require any pesticide sprays.
Although sweet corn does require room, in a 4-by-8-foot raised bed you can grow two rows of corn with the plants in each row spaced 10 inches apart. That's 20 plants. If they each produce two ears, you have a generous harvest of 40 ears of corn.
Prepare the ground for planting by first removing any weeds or unwanted vegetation. Turn the soil to a depth of a shovel blade (about 8 inches), apply a 2-3 inch layer of compost or composted manure and a general-purpose fertilizer following package directions, and thoroughly mix everything together.
When planting sweet corn, plant two or three seeds every 10 inches in the row, burying them about one-half to 1 inch deep, and water in thoroughly. After the seeds germinate and the plants are 3 to 4 inches tall, thin to one plant per 10 inches.
Sidedress sweet corn plants with a nitrogen containing fertilizer (ammonium nitrate, calcium nitrate, ammonium sulfate) when the plants are about 16 inches high and again when the plants are about 36 inches high. Corn benefits from generous fertilization.
Pollination issues
Many of the commonly grown vegetables are self-pollinating (tomatoes) or rely on insects for crosspollination (cucumbers), but corn is wind pollinated. The male flowers that shed the pollen are located at the top of the plant in the tassel. The female flowers are arranged in rows along the cob enclosed by the shucks. A silk is connected to each of the female flowers, and the other ends of the silks hang outside the shuck. At least one pollen grain must land on each silk to pollinate a female flower, which produces one kernel of corn.
Each kernel of corn is the result of a separate act of pollination. So, it is important to plant corn properly to make sure the wind deposits the pollen on the silks.
For that reason, we plant sweet corn in a block planting of several short rows side by side rather than one or two long rows. By planting in blocks, you allow the pollen to move from one plant to another more surely no matter which way the wind is blowing. Ears that are poorly filled with kernels of corn are generally the result of poor pollination.
Some gardeners take this farther and do hand pollination. This only is practical in the small plantings done in backyard gardens. When the tassels at the top of the plants begin to shed the yellow, powdery pollen, tassels are cut and shaken over the silks.
Harvest and use
The best time to harvest sweet corn is in the early morning while the temperature is low. To determine when regular sweet corn is ready to harvest, first check the silks to see if they have begun to dry and turn brown. Then feel the ear. It should feel firm and full.
Peel back a shuck enough to puncture a few kernels on the ears with your thumbnail. When sweet corn is at its highest quality, the juice from the kernels will be milky white and runny. It is not ready when the juice is clear and watery, and corn is over mature and starchy when the juice inside the kernels is thick and dough-like.
Corn usually matures 18 to 24 days after the tassels appear or 15-20 days after the first silks appear. Watch the corn closely because the quality changes fast with the normal sweet varieties. Refrigerate or cook immediately after harvesting.
Dan Gill is a horticulturist with the LSU AgCenter.
