The average last frost date range for USDA hardiness zones two, three and four is from May 1 to May 31. You can plant corn in these zones in early summer, about two weeks after the average date for the last killing frost, when soil temperatures have reached at least 60 degrees F. Because the average first frost dates in these areas are in late summer and early fall, be sure to choose an early maturing variety.
In planting zones five through seven, the average last frost date range is March 30 to April 30. In zone eight, corn can be planted about a month earlier. You can plant corn in these zones in late spring, about two weeks after the average date for last killing frost. Most varieties of corn should grow well in these zones if planted on time because the average first frost date isn't until almost October.
In zones nine and 10, gardeners are less concerned about winter frost than summer heat. Corn can be planted in these zones in early spring, March and April, and late summer, August and September, which gives these zones two corn-growing seasons every year.
Corn grows well in rich, easily worked, well-drained soil. The optimum soil pH for corn is 6.0 to 6.5. Apply a 12-12-12 fertilizer at the rate of about 3 or 4 lbs. per 100 square feet at planting time, and add a nitrogen-heavy fertilizer about halfway through the growing season. Plant seeds 1 to 2 inches deep, spacing plants about 8 to 10 inches apart in rows that are 2 to 3 feet apart. Be sure to plant at least four rows deep to ensure sufficient pollination.