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When to Plant Sweet Corn

Corn seedlings

Sweet corn is a warm-season annual that is commonly planted directly in the garden. It can be started early indoors in individual containers in very short-season regions.

Sow early varieties in the garden 2 weeks after the last frost. Sow mid- and late-season varieties 2 weeks later. The soil should be at least 50°F for good germinations. Seeds planted too early may rot. Seeds germinate in 7 to 10 days.

Start seeds indoors in short-season regions 4 weeks before setting out. Corn does not transplant easily. Be careful not to disrobe the roots, otherwise, growth can be checked.

For a continuous harvest, plant early-, mid-, and late-season varieties together in the garden. Make successive sowings every 3 to 4 weeks up to three months before the first expected fall frost.

Grow corn in loose, well-drained, humus-rich soil. Corn is a heavy feeder and needs high amounts of nitrogen and phosphorus and moderate amounts of potassium. Corn is shallow rooted so mulch to conserve soil moisture and keep down weeds.

Corn Harvest

Corn is ready for harvest when kernels are plump and full of milky liquid. The silks should be brown and feel damp to the touch. To test corn for harvest, pull one of the leaves partially down the ear and press a fingernail into a kernel; if milk spurts out, the ear is ripe.

Green Corn seedlings

Corn planting dates

(These dates are for the Northern Hemisphere)

Average date of the last frostPlanting dates
Jan. 30Feb. 1-Mar. 15
Feb. 8Feb. 10-Apr. 1
Feb. 18Feb. 20-Apr. 15
Feb. 28Mar. 1-Apr. 15
Mar. 10Mar. 10-Apr. 15
Mar. 20Mar. 15-May 1
Mar. 30Mar. 25-May 15
Apr. 10Apr. 10-June 1
Apr. 20Apr. 25-June 15
Apr. 30May 10-June 15
May 10May 10-June 1
May 20May 15-June 1
May 30May 20-June 1
June 10 
Young corn plants
Young corn plants

Corn planting details

  • Sowing depth: 1-2 inches (2.5-5cm)
  • Space between plant after thinning: 9-12 inches (22-30cm)
  • Days to sprout: 7
  • Days to harvest: 65-95
  • Storage period: 7-10 refrigerated
  • Seeds per 100 row feet: ¼ pounds
  • Yield per 100 row feet: 100 ears
  • Suggest varieties: (Early, 60-65 days) Golden Midget, Seneca, Early Sunglow. (Midseason, 70-75 days) Golden Beauty, Early Xtra Sweet, Early Golden Bantam, Kandy Korn, Gold Rush. (Main crop or late varieties, 80-100 days) Golden Bantam, Illini Extra Sweet, Golden Cross Bantam, Country Gentleman, Silver Queen, Stowell’s Evergreen.

More about corn planting at:

How to Grow Corn

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. Harvesttotable.com has more than 10 million visitors each year.

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