Native to North and South America, corn — or maize — was first cultivated some 4,000 years before Columbus set foot in the New World.
Corn is a warm-season vegetable that requires full sun, ample water and deep, rich garden soil to perform well. Warmer temperatures at night also accelerate growth. Prepare the planting site by working in generous amounts of a quality organic compost or well aged animal manure. Plants need to be well protected from frost.
Corn will not germinate if soil temperatures are below 13˚C.
How to Plant
Corn should be planted directly into the soil after it has warmed in the spring (two weeks after your average last-frost date). Sow seeds 2cm deep, 30cm apart. Crops are wind-pollinated, so plant in short rows or blocks to ensure even pollination. Undeveloped kernels indicate uneven pollination. Plant a new crop every two weeks to ensure harvest throughout the gardening season.
Plants are heavy feeders. Fertilize with alfalfa meal, blood meal or other high nitrogen organic fertilizer until tassels develop.
Consider adding kelp meal to vegetable gardens. It’s loaded with micronutrients and is especially good for supplying trace minerals to crops that will be consumed. It will also help guard against plant stresses such as insects, frost, disease and drought.
Make sure that the entire root zone is damp as ears mature by watering at the base of the stalks. Soaking the leaves rather than the roots washes away pollen and reduces the number of kernels that develop.
Harvesting and Storage
Corn is ready to pick three weeks after tassels appear. Look for dark green husks, brown supple silks and plump kernels that squirt “milky” liquid when pinched. Ears taste best when picked in the late afternoon and should be twisted from the plant in a downward motion. Sweet corn requires 65-90 days to reach maturity, depending on the variety.
For best flavor, use within two days of picking and can remaining crop shortly after harvest.
Insect & Disease Problems
Rotate corn with other crops to prevent recurring pest or disease problems. Discourage animal pests with fencing, repellents and scare devices.
White or grayish swellings are signs of corn smut, a common fungal disease that should be treated with organic fungicides.
Seed Saving Instructions
All heirloom varieties are wind pollinated and will cross-pollinate with each other. Varieties should be hand-pollinated or isolated by one mile to ensure purity. Allow ears to dry on plants, harvest and shell.