Corn, Sweet

Growing Tips: Corn, Sweet

Quick Reference:

Planting depth ½ inch spaced 2 to 3 inches apart. Germination: 12 to 18 days. Space between plants in the garden, 3 to 4 inches. Must plant in at least two rows for pollination to occur.

When and where to plant:

Corn is a warm season crop and performs satisfactorily outdoors only in the warmest interior areas of Alaska. Corn seed rots easily in cold, wet soil and will not germinate when the soil temperature is less than 50 degrees F. Corn may be started in the garden 2 to 3 weeks before the last frost when the soil has warmed and is grown under a clear plastic cover. Select the best sunny, warm location available, form a mound of soil 8 to 10 inches high by 12 to 14 inches wide at the top with a slight indentation in the center. Apply plant food and after the soil has warmed, plant seed in the indentation area, firm soil over seed and water well. Cover the mound with clear plastic and secure all 4 edges of the plastic with soil in trenches. Leave plants covered with plastic after the seedlings have emerged, the plants will not sunburn and can remain under the plastic until they are 6 to 8 inches tall which will protect them from a light frost. Using a funnel, water through small holes made in the plastic. After all danger of frost is past slit the plastic and carefully lift the leaves through the slits. Water and apply liquid plant food through the slits in the plastic and ignore any weeds growing under it. The plastic will continue to help raise the soil temperature and corn must have warm soil to mature ears. To assure good pollination plant at least 4 short rows side by side, corn is pollinated by the wind. Corn transplants easily and also may be started indoors in individual 4 to 6 inch plastic pots. Plant 2 to 3 seeds per pot, 3 to 4 weeks before the last frost, then transplant in the garden after the last frost. Corn can be successfully grown in a greenhouse but requires a lot of room. In the greenhouse when the pollen forms on the tassels, shake tassels and use a fan to pollinate the ears. Pollen from the tassels must fall on the silk in the ears for kernels to form.


Water through the slits in the plastic to keep the mound uniformly moist and apply a high nitrogen liquid plant food every 2 weeks.


Pick ears when silks turn brown, ears are firm and kernels begin to show color. For best flavor pick, cook and eat the ears within a couple of hours of harvest.