When Lynne was around 10 years old, she grew a small patch of sweet corn in the garden as a 4-H project. When all was said and done, in response to the prompt on the project report form asking what she’d learned, she wrote, “I learned that raccoons really like corn.”
In spite of the raccoons, she did harvest a few ears and was able to experience the flavor of homegrown sweet corn just minutes from stalk to pot. Still, sweet corn has not been an every-year crop in our garden because of the amount of space it requires. Then last year I saw the success that Ladonna Bruce and Stuart Hall have growing corn in their Stockton Springs garden. They convinced me that sweet corn can and should be a part of every home garden, no matter how small.
Ladonna and Stuart use a modified version of the Three Sisters Garden to thwart the raccoons. They grow winter squash at the feet of their corn plants, letting the prickly leaves and stems keep the tender-footed raccoons at bay. Last year they harvested about four-dozen ears from 25 plants, the raccoons absconding with only the few ears that could be reached from the walkways.
According to Native American legend, corn, squash and beans are three inseparable sisters who only grow and thrive together. Planting these three crops together in the same garden space is a widespread tradition among many Native American farming societies, a sustainable system that provides both long-term soil fertility and a healthful diet.
The corn stalks provide a natural pole for the bean vines to climb while the beans fix atmospheric nitrogen on their roots, improving the fertility of the entire plot. The beans also help to stabilize the corn plants against root and stem lodging. The squash vines form a living mulch over the soil, slowing weed emergence and preventing evaporation of soil moisture, and the spiny squash leaves and stems discourage predators, including the masked bandits.
Planting a Three Sisters Garden
Sweet corn grows best in loose, rich soil with a pH between 6.0 and 6.5; heavy soil inhibits rooting. Wait to plant your Three Sisters Garden until soil temperatures have settled above 60 degrees, since corn kernels will not germinate in cold soil.
After incorporating decomposed stable manure or compost into the soil, make mounds spaced about three feet apart, each 12 inches high and 24 inches across. If possible, group the mounds in a block, rather than in one long row, to enhance wind pollination.
Flatten the tops of the mounds, then plant five to six corn seeds in a small circle within the center of each mound. Plant the kernels an inch deep in heavy soil, two inches deep in light sandy soil.
When the corn seedlings are about five inches high (about two weeks after sowing), plant seven or eight pole bean seeds in a circle about six inches away from the corn seeds. Wait another week, then sow seven or eight squash seeds around the edge of each mound, about 12 inches from the beans.
As the plants grow, thin the corn in each mound to the sturdiest two or three seedlings. Also thin the beans and squash, removing weak seedlings and keeping three vigorous seedlings of each evenly spaced around the mound. Help the bean seedlings to start climbing the corn stalks by gently propping their growing points against the stalks.
Sweet corn types
Sweet corn is a genetic mutation of field corn, producing kernels with mostly sugar rather than starch. In the older sweet corn varieties, the sugar rapidly converts to starch after the prime harvest stage. Recent hybrids, however, have even higher sugar concentration and slower conversion of sugar to starch.
In seed catalogs you will find sweet corn varieties separated into genetic groups, the best of which in terms of tenderness and sweetness are the “Sugar Enhanced” types (se and se+ genes). This year, I’m planting Trinity sweet corn, both in Marjorie’s Garden and in the Eastport Schoolyard Garden. It is a bicolor sugar-enhanced variety with excellent flavor, maturing in 68 days. It grows to five feet tall, not so tall that it would likely blow over in high winds.
I checked in with Harvard Jordan at the Ellsworth Feed and Seed and he is high on Ambrosia, another sugar-enhanced bicolor variety that matures in 75 days and grows to six-and-a-half feet tall. He did mention that it toppled in a strong wind storm one year.
Sweet corn growing tips
Don’t be in a rush to get your corn seeds in the ground. Planting corn too early results in poor stands and retarded growth. And start with fresh seeds rather than leftovers from last year. Even under ideal storage conditions, corn seed is short-lived.
Sweet corn is a heavy feeder. In addition to digging in the decomposed manure or compost at planting, apply additional nitrogen when the corn plants are eight inches tall and again when the plants are tasseling. This can be accomplished with a variety of organic products, including blood meal, soy meal, fish meal and alfalfa meal. All of these are dry materials that can be cast directly over the soil between the plants, followed by washing the dust from the leaves to avoid burning. Follow label directs carefully in calculating the correct amount to apply.
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