Growing Corn

Some corn kernels don’t fill out at the tips of the corn ears

Sometimes the tips of the ears, or kernels even deep down in the ear, don’t fill out. That’s okay.

Sinking your teeth into a perfectly ripened ear of sweet corn is one of the finest pleasures of summer, and early-maturing sweet corn varieties like Sugar Buns will offer a harvest sooner than you might think. You will need to wait 3 weeks longer for Silver Queen, but your reward will be kernels packed with sweetness and rich corn flavor.

Corn needs plenty of space for two reasons — it is a heavy feeder, and it is primarily pollinated by wind. As grains of pollen are shed by the tassels that grow from the plants’ tops, they must find their way to the delicate strands of silk that emerge from newly formed ears. To make sure silks are nicely showered with pollen, grow corn in blocks of short rows rather than in a long, single row. In a small garden, 15 plants set 1 foot apart can be grown in a 3 x 5-foot bed. Growing corn on this tiny scale is a good way to introduce yourself to the crop if you’ve never grown it. After the first year you will probably want to increase the size of the planting to at least 4 rows 10 feet long.

Corn plants are not like tomatoes or most other vegetables, which bear over a long period of time. Instead, they form a few ears per stalk and they are finished. Because of this, gardeners who have the space often make 2 or 3 plantings 2 weeks apart to keep the harvest coming.

Soil, Planting, and Care

Corn planted in a garden with black groundcover to warm the soil

In areas where the soil stays cool longer, cover the ground with black plastic or IRT film a week or two before planting and set plants through holes cut into the material.

Corn needs a spot with that gets full sun and has fertile, well-drained soil with a pH of 6.0 to 6.8. Seedlings can be set out as soon as the last spring frost has passed. Space plants 8 to 12 inches apart. In case of a surprise late frost, be prepared to cover seedlings with a fabric row cover. In cold climates you can plant in a raised bed covered with black or IRT plastic (infrared transmitting plastic) that will warm the soil. If possible, lay the plastic a week or so before planting.

Plan to fertilize twice because corn is a hungry plant. Before setting out seedlings, amend the soil with compost and mix a balanced organic or timed-release fertilizer into the soil. About a cup of 10-10-10 per 10 feet of row is a good general rate, but be sure to check and follow rates given on the label of any fertilizer you are using. About 6 weeks or so later, when the plants start to produce tassels, fertilize them again. (If you amend the soil with cottonseed meal or other high-nitrogen amendment, it may not be necessary to feed the second time.) Use a hoe or trowel to mix the fertilizer into the top inch of soil between the plants. After this booster feeding, water your corn once or twice weekly if the weather is hot and dry.

Normal plants should grow fast with dark green healthy leaves. Corn will tell you if it is hungry by turning very light green. If so, feed again.

Corn grows fast and needs lots of water to grow properly. It also has shallow roots that make it susceptible to drought. Soaker hoses will insure that your corn gets the water it needs. However, for a large planting, soaker hoses may not be practical.

Hopi and Navaho Techniques
Native Americans in arid climates planted corn in basins to catch spring rainwater and help keep the corn roots down where water would be available longer. The basin was about 4 inches deep and 2 to 3 feet wide with a raised ridge made from the excavated soil around it. Plants were arranged so that they formed a spiral from the center to help with support in wind and with pollination. If you live in an arid climate or a hot climate and have poor sandy soil, as in the Coastal Plains, this technique could help ensure a good harvest.


Corn growing in a garden with other vegetables

Corn plants need plenty of space because they are large, but they can be planted with other vegetables in a large garden. Plant corn in blocks of rows at least 4 across so the wind can scatter their pollen to neighboring plants.

Corn plants that are blown over by gusty storms usually right themselves after a few days of sunny weather. As you shuck and clean your corn, pop off ear tips damaged by corn earworms. The different types of corn should not be allowed to cross-pollinate, so plant them in such a way that pollen from one type does not reach another type. If you or a nearby neighbor grow multiple types, be sure that they are isolated by at least 250 feet or that their timing is such that they are not in bloom at the same time. If not, the pollen from types that are not the same can muddy their characteristics to the point of ruining sweetness and flavor.

Raccoons love corn. The most effective way to keep them out of the patch is to surround it with a fence with 2 strands of electric wire 4 and 12 inches from the ground. Some gardeners have been successful with throwing blackbird netting over and around the plants because some raccoons don’t like it. The methods for keeping raccoons out of corn are as varied as gardeners themselves. We’ve heard of people putting flashing lights in the corn patch, putting a radio on a timer to blare loud music, laying newspaper in rows because the raccoons don’t like to walk on the crinkly paper, spraying animal repellents, and other techniques, but a physical barrier such as an electrified fence seems to be the most reliable.

Harvest and Storage

Know when to harvest corn from the garden by looking at the silks. Brown silks mean the corn is ready.

Corn is ready to harvest when the silks are brown and the ear is filled out. Peel back the tip of the ear to check the sap.

Most corn plants will yield at least 2 ears per stalk. Hybrids may yield more. To see if an ear is ready for harvest, look at the silks. They should be brown and dry with just a little fresh green at the base. Squeeze the husk to see if the ear inside feels plump, not skinny. If you’re still not sure if the ear seems ripe, check by peeling just enough of the husk back to expose a couple of inches of the ear. Poke a kernel with your fingernail. The corn is ready to pick if it bleeds a light milky sap like skim milk. If the liquid is clear, the ear is not ready. Ears that are too ripe will look too milky, like cream versus skim milk; they often taste starchy. Remove them right away.

Perfectly ripened ears also taste sugary-sweet when sampled raw. When possible, harvest sweet corn in the morning, when the ears are cool. To remove the ear, use one hand to hold the corn stalk and the other to pull the ear down and away from the stalk, twisting a little until it breaks off.

Place harvested ears in the refrigerator right away. When kept chilled, they should hold much of their sweet flavor for up to a week, though they’ll taste best if eaten as close to harvesting as possible. Corn can be blanched and frozen, on or off the cob.



What are the reddish spots showing up on my corn leaves?

This disease is called rust and cannot be controlled. Typically, rust won’t damage corn yields, unless growing conditions are exceedingly stressful (drought, flood, etc.).

When is the best time of day to harvest corn?

Sweet corn is ready to pick when a test kernel pierced with your fingernail bleeds a light milky sap, like skim milk. Ripe ears will taste sugary-sweet when sampled raw. After picking, the sugar in corn turns to starch, reducing sweetness. Knowing this, some people harvest corn right before cooking, thinking they’re preserving the sweetness. Corn actually has the highest sugar content early in the morning, before the sun touches them. If you want the sweetest flavor, pick ears early in the morning and refrigerate in the husk until cooking.

How do I know if ears are ripe?

Try to avoid peeling the husk to peek at ears. It’s best to keep husks in place until cooking. Ripe ears feel full and rounded and have silk that’s dried and brown on the ends. If you do peek at end kernels, pierce a kernel and look for milky sapÑthat’s another sign of ripeness.

I was weeding around the corn with a hoe yesterday. Today stalks are wilted, even though the soil is moist. What is happening?

Corn is a shallow rooted plant. You might have broken corn roots if you hoed weeds deeply, chopping into soil near stalks. Keep weeds in check by cultivating frequently so you don’t have to do much more than scuffle the soil to dislodge offenders.

The corn in my garden is attracting birds and raccoons. What can I do to protect the harvest?

A scarecrow can keep birds at bay if you dress it in loose fitting clothes that will move in the wind and decorate it with strips of aluminum foil to flutter and reflect light. Ideally, move your scarecrow every few days so birds don’t become accustomed to it. Raccoons require more aggressive tactics. Try a two-strand electric fence (one strand 4 inches off the ground, the second strand 12 inches high). Turn on the power about a week before you think the first ears will be ripe.

Shoots are coming out of my corn stalks near the ground. Will they produce corn?

These shoots are called suckers and won’t form ears. While it’s not necessary to remove them, many experienced home gardeners believe removing suckers produces larger, better quality ears. This hasn’t been proven. If you do choose to remove suckers, snap them off while they’re less than 3 inches tall to avoid damaging the stalk.

My garden space is small. Can I grow corn without planting it in long rows?

Corn is wind pollinated, and research has proven that it’s actually better to arrange plants in blocks of short rows rather than long rows. That means even small gardens can squeeze in a corn crop. Arrange corn in at least four rows side-by-side, spacing rows 12-24 inches apart. Wind will blow the pollen from one corn stalk to another.