The Vegetable Garden

Corn

    Sweet corn is a warm-season vegetable that can be grown easily in any garden with sufficient light, fertility, growing season and space. It is especially popular with home gardeners because it tastes appreciably better when it is harvested and eaten fresh from the garden. Successive plantings can yield continual harvests from early summer until frost if the weather cooperates.

    Sweet corn may be divided into three distinct types according to genetic background: normal sugary (SU), sugary enhancer (SE) and supersweet (Sh2).

    Standard sweet corn varieties contain a "sugary (SU) gene" that is responsible for the sweetness and creamy texture of the kernels. SUs are best suited to being picked, husked and eaten within a very short time. In the home garden, this is sometimes possible but not always practical. The old adage was "start the water boiling, run to the patch, pick and husk the corn, run back to the pot, cook the corn, and eat or process immediately."


    Sugary enhancer hybrids contain the sugary enhancer (SE) gene, that significantly raises the sugar content above standard SUs while retaining the tenderness and creamy texture of standard varieties. The taste, tenderness and texture are outstanding. SEs are the gourmet corns of choice for home gardeners because they contain the best qualities of both SU and Sh2 types. Fresh from the garden, virtually all current SE releases have eating quality that is superior to all other types. No isolation from standard SUs is necessary.

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    Supersweet hybrids contain the shrunken -2 gene and have a higher sugar content than the standard SU varieties. The kernels of the extra-sweet varieties have a crispy, tough-skinned texture and contain low amounts of the water-soluble polysaccharides that impart the creamy texture and "corny" flavor to other sweet corn varieties. Although the lack of creamy texture is not especially noticeable in fresh corn on the cob, it affects the quality of frozen and canned corn, as does the toughness of the seed coat. Unless corn must be stored, shipped or mechanically harvested, SEs are superior in eating quality to Sh2s.

    Supersweets (Sh2) should be isolated from any other type of corn tasseling at the same time to ensure sweetness and tenderness. Their pollen is weak and easily supplanted by other types, which causes the kernel to revert to a form with the toughness and starchiness of field corn. Because corn is wind-pollinated, this isolation distance can be 500 feet or more, especially downwind.

     


    Varieties

    Most of the varieties listed here (like nearly all sweet corn sold today) are hybrids. They are arranged by genetic type and kernel color. The maturity dates are relative because the actual number of days to harvest varies from year to year and location to location.

     

     

    Standard (SU)

    Yellow Harvest Ear Size Comments

    Earlivee

    58 days

    7"-14 rows

    extra early

    Golden Cross Bantam

    85 days

    8"-12 to 14 rows

    old home-garden variety

    Iochief

    86 days

    8"-14 to 16 rows

    popular midseason variety

    Jubilee

    82 days

    8"-16 rows

    high yield; deep, narrow kernels; excellent for canning

    NK-199

    84 days

    8"-18 to 20 rows

    extremely thick, attractive ears; silks easily removed

    Seneca Horizon

    65 days

    7"-16 to 18 rows

    excellent quality

    Sundance

    69 days

    1/2"-14 rows

    best cold-soil tolerance, early season vigor; handsome ears

    White Harvest Ear Size Comments

    Pearl White

    75 days

    7 to 8"-12 to 16 rows

    good cool-soil and drought tolerance; easy snapping

    Platinum Lady

    86 days

    8 1/2"-14 rows

    delicate flavor; tender kernels; slender, elegant ears

    Silver Queen

    92 days

    8 to 9"-14 to 16 rows

    dark green flag leaves, attractive ears; standard, high-quality white corn; resistant to bacterial wilt and Helminthosporium

    Bicolor Harvest Ear Size Comments

    BiQueen

    92 days

    8 to 9"-16 rows

    like a bicolor Silver Queen

    Butter & Sugar

    75 days

    7"-14 rows

    popular for home garden

    Honey & Cream

    80 days

    7"-12 to 14 rows

    sweet, tender; long, tight husks

    Quickie

    64 days

    7 1/2"-12 rows

    earliest SU bicolor

    Sugar & Gold

    67 days

    6 1/2"-10 to 12 rows

    husk green, with reddish tinge; excellent quality; prefers cooler-season areas



    Most of the varieties listed here (like nearly all sweet corn sold today) are hybrids. They are arranged by genetic type and kernel color. The maturity dates are relative because the actual number of days to harvest varies from year to year and location to location.

     

     

    Sugary Extender (SE)


    Harvest Ear Size Comments

    Bodacious

    72 days

    8"-16 to 18 rows

    superior flavor, holding ability; ears snap easily; prefers warm soil

    Champ

    68 days

    8"-16 to 18 rows

    excellent eating quality, tip cover

    Incredible

    83 days

    8 to 9"-18 rows

    big, flavorful ears; excellent appearance, yield

    Kandy Korn

    89 days

    8"-14 to 16 rows

    purplish red-streaked ear flags, excellent quality, long shelf life

    Maple Sweet

    70 days

    7 1/2"-14 to 16 rows

    excellent flavor, easy snapping

    Merlin

    84 days

    9"-20 to 22 rows

    superior flavor, ear size, disease tolerance; easy snapping

    Miracle

    84 days

    9 1/2"-16 to 18 rows

    good holding quality; large, tender, attractive, tasty ears

    Precocious

    66 days

    7"-12 to 14 rows

    very early; excellent eating, good tipfill

    Spring Treat

    67 days

    7"-14 rows

    easy snapping, straight rows of kernels

    Sugar Buns

    72 days

    7 1/2"-14 rows

    excellent flavor; attractive, relatively small ears; deep kernels

    Terminator

    83 days

    9"-20 rows

    large ears, superior disease resistance

    Tuxedo

    75 days

    7 1/2"-16 to 20 rows

    excellent early vigor; good tipfill, husk cover; excellent eating quality; tolerant to Stewart’s wilt, and smut

    White Harvest Ear Size Comments

    Alpine

    79 days

    8"-16 rows

    widely adapted; excellent yield; cool-soil tolerance; attractive ear

    Argent

    86 days

    8 to 9"-16 rows

    good cold-soil vigor; tolerant to Stewart’s wilt; like a white Incredible

    Avalanche

    78 days

    8"-16 rows

    excellent eating; good ear appearance

    Cotton Candy

    72 days

    7 to 8"-16 to 18

    extended harvest; reddish green stalks

    Divinity

    78 days

    8"-16 rows

    excellent flavor, tenderness; snow white color; excellent tip cover; tolerant to drought, Stewart’s wilt

    Pristine

    76 days

    8 to 9"-16 rows

    terrific eating quality, tolerant to Stewart’s wilt

    Seneca Starshine

    71 days

    7 to 8"-16 rows

    blocky ears, with pure white kernels; excellent tenderness, flavor, appearance; prefers 50°F or higher soil temperature for germination

    Seneca White Knight

    74 days

    8 to 9"-16 rows

    high quality; attractive ears; great taste

    Snowbelle

    79 days

    7 to 8"-14 to 16 rows

    creamy texture; pretty, compact ears

    Spring Snow

    65 days

    7 to 8"-12 rows

    excellent husk cover; very early; attractive ears; very tender kernels; compact plant

    Sugar Snow

    71 days

    8 to 9"-16 rows

    extremely sweet, snow white kernels; good cold-soil tolerance

    Telstar

    79 days

    8"-16 rows

    vigorous; dark green flag leaves; tasty; attractive ear

    Ambrosia

    75 days

    8"-16 rows

    good spring vigor; fairly large, tasty ears; tolerant to Stewart’s wilt

    Calico Belle

    79 days

    8"-16 to 18 rows

    high yield; attractive; delicious taste; good disease tolerance

    D’Artagnan

    71 days

    8"-16 rows

    superior quality in an early SE bicolor

    Diamonds & Gold

    79 days

    8"-18 rows

    sweet, tender; good tipfill; attractive dark green ears

    Double Delight

    85 days

    9"-16 rows

    large, tasty ears; dark green husk; like a bicolor Incredible

    Double Gem

    74 days

    8 to 9"-16 to 18 rows

    excellent eating quality; blocky ears; usually double ears on stalks

    Kiss ‘N Tell

    68 days

    7 to 8"-14 to 16 rows

    two ears per stalk; good tipfill

    Lancelot

    80 days

    8"-16 to 18 rows

    vigorous, stress-tolerant plant; good yields; high quality ears under adverse conditions

    Medley

    73 days

    8"-16 rows

    dark green flags; good tip cover; tolerant to Stewart’s wilt

    Peaches & Cream

    83 days

    8"-16 to 18 rows

    tasty, poplar home-garden variety; vigorous plant; good ear protection

    Seneca Brave

    73 days

    8"-18 to 20 rows

    husky, excellent quality ears; strong plants

    Seneca Dawn

    69 days

    7 to 8"-14 to 16 rows

    excellent early bicolor; good vigor, eating quality



    Most of the varieties listed here (like nearly all sweet corn sold today) are hybrids. They are arranged by genetic type and kernel color. The maturity dates are relative because the actual number of days to harvest varies from year to year and location to location.

     

     

    Supersweet (Sh2)

    Yellow Harvest Ear Size Comments

    ChallengerCrisp ‘N Sweet

    85 days

    9"-18 rows

    high yield; excellent disease resistance; good germination, seedling vigor

    Early Xtra Sweet

    70 days

    8"-16 rows

    like the original, but earlier

    Excel

    82 days

    8 1/2" - 16 rows

    exceptionally high yield, easy to harvest

    Illini Gold

    79 days

    8 1/2"-16 rows

    midseason supersweet

    Illini Xtra Sweet

    85 days

    8"-14 to 16 rows

    the original SH2 supersweet hybrid

    Jubilee Supersweet

    83 days

    9"-18 rows

    excellent home garden supersweet

    Showcase

    83 days

    8"

    large ear on short plant, outstanding eating quality

    White Harvest Ear Size Comments

    Aspen

    83 days

    8 to 9"-16 rows

    large, attractive ears; high eating quality

    Camelot

    86 days

    8"-18 to 20 rows

    clean, sturdy plants; excellent quality, holding traits

    How Sweet It Is

    85 days

    8"-16 rows

    All-America Selection winner, sensitive to cold soil, holds quality well

    Pegasus

    85 days

    8 1/2"-18 rows

    good cold soil germination, vigor

    Treasure

    83 days

    8 1/2"-18 rows

    good vigor, seedling emergence

    Bicolor Harvest Ear size Comments

    Aloha

    82 days

    9"-16 rows

    excellent appearance

    Dazzle

    82 days

    8"-16 to 18 rows

    good looking ear; good disease resistance; creamy texture

    Honey ‘N Pearl

    78 days

    8 1/2"-16 rows

    1988 All-America Selection winner, stands well, excellent quality

    Hudson

    83 days

    8"-18 rows

    smooth, well-filled ears; superior eating quality, tenderness

    Phenomenal

    85 days

    8 1/2"-16 rows

    excellent eating quality, beautiful ears

    Radiance

    73 days

    8"-16 to 18 rows

    excellent seedling emergence, plant vigor

    Open-Pollinated (SU)
    Yellow Harvest Ear size Comments

    Ashworth

    69 days

    6 to 7" ears, 12 rows

    good cold soil germination; good flavor for an early type

    Golden Bantam

    82 days

    6 to 7"ears, 10 to 14 rows

    rich corn flavor, sweet, tender

    White Harvest Ear size Comments

    Country Gentleman

    96 days

    7" ears, kernels not in rows

    very tender, shoe-peg type; drought resistant

    Stowell’s Evergreen

    100 days

    9"ears, 18 to 20 rows

    big, juicy, white kernels; ripen over long period

    Trucker’s Favorite

    95 days

    8 to 9" ears, 14 rows

    delicious white kernels, high yields

    Bicolor Harvest Ear size Comments

    Double Standard

    73 days

    7"ears, 12 to 14 rows

    first bicolor open-pollinated type; good cold soil germination good flavor, tenderness; traditional corn taste

    Black Harvest Ear size Comments

    Black Aztec

    75 days

    7"ears, 8 to 10 rows

    vigorous drought tolerant; sweet white kernels in roasting ear stage, dark blue-black at maturity; good for blue corn meal


    When To Plant

    Sweet corn requires warm soil for germination (above 55°F for standard sweet corn varieties and about 65°F for supersweet varieties). Early plantings of standard sweet corn should be made at, or just before, the mean frost-free date unless you use special soil-warming protection such as clear polyethylene mulch film.

    For a continuous supply of sweet corn throughout the summer, plant an early variety, a second early variety and a main-crop variety in the first planting. For example, you may wish to select Sundance (69 days) for the first early variety, Tuxedo (75 days) for the second early variety and Incredible (83 days) for the main-crop variety. Make a second planting and successive plantings of your favorite main-crop or late variety when three to four leaves have appeared on the seedlings in the previous planting. Plantings can be made as late as the first week of July.

    Spacing & Depth

    Plant the kernels (seeds) 1/2 inch deep in cool, moist soils and 1 to 1 1/2 inches deep in warm, dry soils. Space the kernels 9 to 12 inches apart in the row. Plant two or more rows of each variety side by side to ensure good pollination and ear development. Allow 30 to 36 inches between rows.

    All sweet corns should be protected from possible cross-pollination by other types of corn (field, pop or flint). If you plant supersweet or synergistic sweet corn varieties, plan your garden arrangement and planting schedule so as to prevent cross-pollination between these varieties and with any other corn, including nonSh2 sweet corns. Supersweet varieties pollinated by standard sweet corn, popcorn or field corn do not develop a high sugar content and are starchy. Cross-pollination between yellow and white sweet corn varieties of the same type affects only the appearance of the white corn, not the eating quality.

    Care

    Cultivate shallowly to control weeds. Chemical herbicides are not recommended for home gardens. Although corn is a warm-weather crop, lack of water at critical periods can seriously reduce quality and yield. If rainfall is deficient, irrigate thoroughly during emergence of the tassels, silking and maturation of the ears.

    Hot, drought conditions during pollination result in missing kernels, small ears and poor development of the tips of the ears. Side-dress nitrogen fertilizer when the plants are 12 to 18 inches tall.

    Some sweet corn varieties produce more side shoots or "suckers" than others. Removing these side shoots is time consuming and does not improve yields.


    Harvesting

    Each cornstalk should produce at least one large ear. Under good growing conditions (correct spacing; freedom from weeds, insects and disease; and adequate moisture and fertility), many varieties produce a second ear. This second ear is usually smaller and develops later than the first ear.

    Sweet corn ears should be picked during the "milk stage" when the kernels are fully formed but not fully mature. This stage occurs about 20 days after the appearance of the first silk strands. The kernels are smooth and plump and the juice in the kernel appears milky when punctured with a thumbnail. Sweet corn remains in the milk stage less than a week. As harvest time approaches, check frequently to make sure that the kernels do not become too mature and doughy. Other signs that indicate when the corn is ready for harvest are drying and browning of the silks, fullness of the tip kernels and firmness of the unhusked ears.

    To harvest, snap off the ears by hand with a quick, firm, downward push, twist and pull. The ears should be eaten, processed or refrigerated as soon as possible. At summer temperatures, the sugar in sweet corn quickly decreases and the starch increases.

    Cut or pull out the cornstalks immediately after harvest and put them in a compost pile. Cut the stalks in one foot lengths or shred them to hasten decay.

    Common Problems

    Corn earworms are a problem in sweet corn every year. Earlier plantings are not badly infested in areas where the pest does not overwinter, but later harvests usually have severe earworm damage unless timely control measures are followed. Corn earworms deposit eggs on the developing silks or on the leaves near the ear. The tiny caterpillars follow the silks down into the ear, where they feed on the tip. Only one corn earworm will be found per ear because the caterpillars are cannibalistic, with the largest devouring any others present. Once the worm is inside the protective husk covering, there is no effective control. Anything that restricts the worm-such as tightening the tip of the husk with a rubber band or clothespin after the silk appears, or inserting mineral oil (1/2 medicine dropperful) in the silk tube-helps to decrease the damage.

    Corn rootworm beetles may cause extensive silk damage that interferes with pollination. Later plantings usually suffer the greatest damage, especially where field corn is grown. Beetles multiply in early plantings of field corn, mature and migrate to plantings of young, tender sweet corn. Silk and the young, tender, green leaves are preferred feeding sites. If infestation is sufficient to remove silk before pollination, cobs develop without a full set of kernels. Control measures must be taken as the silk emerges.

    European corn borers damage stalks, tassels and ears. As their name indicates, corn borers bore into the plant; and the stalks break over when damage is severe. Corn borers also may bore into the cob and be found after cooking. A suggested insecticide can be applied at 5 day intervals, beginning when eggs hatch in June. Spray applications for earworms usually give adequate control of corn borers.

    Flea beetles often attack early in the spring as the corn plants emerge through the soil. Flea beetles can be quite damaging when numerous and they may carry Stewart’s bacterial wilt disease.

    Stewart’s wilt is a bacterial disease spread by the flea beetle. This disease causes yellow streaks in the leaves, stunting and death of young plants of susceptible varieties. The disease occurs more frequently in the southern states and is not severe after cold winters or when resistant varieties are planted. If possible, plant varieties with good resistance.


    Smut is caused by a fungus that invades the kernels. It develops as a swollen black pustule (gall) in the ear and sometimes infects the tassel. Some sweet corn varieties are more tolerant to smut than others. Smut occurs most frequently on white varieties and is often severe when extremely dry or hot weather occurs just before and during tasseling. Remove and destroy smut galls while they are moist and firm. Do not discard these galls in or near the garden. Place in the garbage or burn them. The smut is not poisonous, but it is unpleasant to handle. Break off the infected part of the ear. The remainder is suitable for eating.

    The immature smut fungus or "maize mushroom" is highly prized in Mexican cooking. Harvest when the fungus is expanded, but before it becomes black and dried out. The time generally is about 2 to 3 days before the sweet corn reaches peak eating quality.