Ear of yellow corn - corn growing guide

An annual crop, corn produces ears of bi-colored, white, and yellow kernels. To grow corn, a long, frost-free growing season is necessary. As a member of the grass family (Poaceae), corn relies on wind to pollinate its flowers, so instead of long, single rows, it should be planted in blocks of short rows. Corn comes in early, mid, and late-season varieties. Early-season varieties are the quickest to mature whereas late-season may take the entire growing season. For an extended harvest, plant varieties with different “days to maturity.”

Planting and Growing Information:

It’s generally not recommended to begin corn indoors. It’s best to start them directly in the garden so that their sensitive roots aren’t disturbed as a result of transplanting. Outdoors, direct-sow corn seeds approximately two weeks after the last spring frost date. Since corn requires a fairly long growing period with warm weather, it’s crucial to get corn planted as soon as possible. If you live in an area with a shorter growing season, choose an early variety that will mature well before the first frost. The key to successful germination is soil temperature, and for corn, it should be at least 60°F, or 65°F for super sweet varieties. In colder areas, if necessary, the ground should be warmed by a black plastic cover. Plant seeds through holes in the plastic. Plant another crop to spread out the harvest a couple of weeks after planting your first round of corn.

The soil should be well-draining yet consistently moist with a slightly acidic to neutral pH as corn tends to suck up a lot of water. For sufficient pollination, plan your plot right. Rather than planting one or two long rows of corn, plant “blocks” of corn at least four rows deep. This ensures that the corn—which is pollinated by winds and not bees—has a stronger chance of producing viable, full ears. Another suggestion, for example, in a 10×10-foot plot, lay a drip line in ever-increasing circles spaced 1 foot apart and plant a seed at each emitter.

To speed up germination, moisten seeds, wrap in moist paper towels, and store in a plastic bag for 24 hours. Sow seeds about 1½ to 2 inches deep and 4 to 6 inches apart in rows 30 to 36 inches apart. Always make sure to water well at planting time. When the young corn plants reach 3 to 4 inches tall, thin them so that they are 8 to 12 inches apart. Always be careful not to damage the roots of the corn when weeding around the plants. Make sure to keep corn well-watered because it has shallow roots and can become stressed by drought. An inch of rainfall per week is sufficient; water more if conditions are especially hot or if your soil is sandy. In order to keep stalks standing straight during high winds, mound soil around the base of 12-inch-tall plants. Tillers, or suckers, are secondary shoots that may develop low on the stalk later in season; however, they do not adversely impact the main stalk.


Given corn plants are picky about their soil, it’s ideal that aged manure or compost should be worked into the soil in the fall prior to planting and allowed to overwinter in the soil. By spring, the soil will be fertile and ready for corn. If that’s not possible to do, simply mix in aged compost prior to planting. Once the corn reaches 8 inches tall, side-dress plants with a high-nitrogen fertilizer; repeat when it’s knee high (18 inches). You may choose to fertilize at planting time with a 10-10-10 fertilizer; corn is meant to grow rapidly. However, if you’re certain that the soil is adequate, this step can be skipped.


The warmer the air, the quicker corn matures. It’s usually ripe about 15 to 23 days after silking—and sooner if temperatures are exceptionally high. Ears should be rounded or blunt, not pointed, with tassels turning brown and kernels full and milky. Test the corn by pulling down some husk and piercing a kernel with a fingernail. If it’s white or milky, it’s ready. The milk stage is brief; in hotter weather (over 85°F), corn is at peak for only 1 to 2 days, so make sure to frequently check it. Corn harvested a few days after milk stage will not be as sweet. Pull ears downward and twist to take off stalk. Given sugary (su) varieties begin to lose their sweetness soon after harvesting, use them as soon as possible. Immediately after picking, prepare for eating or preserving. If immature corn suffers a late-season frost, the plants and cobs can be damaged and will result in the death of a plant or poor-tasting corn.