Choose a site that gets full sun and has soil with a pH of 6.0 to 6.8. Corn needs soil that's simultaneously rich, moisture-retentive and well-draining; digging in plenty of compost and well-cured manure will ensure the magic combination.
Buy corn plants at the nursery if your growing season is on the shorter side of acceptable. Otherwise, plant seeds outdoors at least a week after the last frost and when the soil temperature has reached at least 55 degrees F (65 degrees for supersweet varieties).
Sow seeds 1 to 1/2 inch deep, 4 to 6 inches apart. For best results, plant in hills, with several plants to a hill and the hills grouped in clusters rather than long rows (see "How to Plant Vegetable Seeds Outdoors").
Thin plants to a foot apart when they're 3 to 4 inches tall, and mulch when the ground has warmed to deter weeds and retain moisture.
Make sure plants get at least an inch of water a week, but never water from above - it can wash away pollen.
Feed plants with a balanced liquid organic fertilizer three times: when they reach 10 inches, then 18 inches, and when tassels appear.
Harvest when husks are dark green, silks are dry and brown but still supple, and full-size kernels reach to the top of the ear. For most varieties, that will be about 20 days after the silks appear.