key growing information

Old-Fashioned Sweet Corn: Growing Information

How to grow open-pollinated sweet corn: spacing and block planting for pollination, succession planting, pest management, harvest timing and seeding rates.

By Hensley’s Seed Co. September 3, 2026

Old Fashioned Sweet Corn - Key Growing Information

Several ears of freshly shucked and unshucked, old-fashioned sweet corn.

SCIENTIFIC NAME:

Zea mays

CULTURE:

Open-pollinated (OP), or standard, corn varieties come true from saved seed year after year. They aren't as uniform or tender as modern hybrids; many people love their old-time chewy texture and flavor, but if you haven't grown them before, start with a small planting. Plant ¾–1" deep, 6–7" apart (or 2 seeds every 9", later thinned to one), in rows 30–36" apart; sow a little more heavily if the seed is untreated. Corn is wind-pollinated, so plant in blocks of at least 4 rows to get well-filled ears. You can keep planting into early summer, and many growers stretch the season by growing several varieties with different maturity dates.

INSECT PESTS:

Your local Cooperative Extension office can advise on integrated pest management. Plowing under or pulling and composting stalks promptly after harvest reduces insect pressure on next year's corn.

HARVEST:

Pick when kernels are plump and milky; the silks drying and turning brown is the usual sign. Note the day when about half the plants are silking: ears are generally ready 18–24 days later, sooner in hot weather.

DAYS TO MATURITY:

Weather and planting date shift maturity a great deal, so use these numbers to compare varieties rather than to predict an exact harvest day.

AVG. SEEDING RATE:

At 2 seeds per foot in rows 36" apart: 1,000 seeds sow about 500', 5,000 about 2,500', 25,000 about 12,500'; plan on roughly 30,000 seeds per acre.

SEEDS/LB.:

Avg. 2,100.

PACKET:

150 seeds per packet, enough for about 75' at 2 seeds per foot.