How to Grow Corn

Days to germination: 4 to 10 days
Days to harvest: 60 to 90 days
Light requirements: Full sun
Water requirements: Frequently and regularly
Soil: Very rich and well-drained
Container: Possible, but not ideal

Introduction

Corn can be a challenge for the novice gardener, but a big harvest of delicious corn can make the effort worth it. Growing corn is all about temperature, so some of the timing guidelines can be kind of vague and are usually not based on the calendar.

You can eat corn right off the cob, or take the kernels off the cob for easier eating as well as longer-term storage. New varieties of corn have high sugar content, making for some very sweet corn options. Health-wise, corn is high in several B vitamins, beta-carotene, and fiber.

Starting from Seed

Corn is typically seeded right into the garden, and not grown by transplants. Corn seed must be planted in warm soil, so don’t get ahead of yourself and try planting early in the spring to get a head-start. The soil needs to be at least 60F, which means you will be planting after your last frost date.

Choose your corn plot carefully. These will most likely be some of the tallest plants in your garden and will shade out other plants. Plants like lettuce or radishes might not mind, but most of your vegetables will suffer if their sun is blocked out.

When preparing the soil, add aged manure or compost (or both) to provide the nutrients that “heavy-feeding” corn will need. Plant more seed than you need (2 inches deep), and thin out any extras so that the remaining plants are 2 inches apart.

Corn is somewhat unique for the vegetable garden, in that it is a wind-pollinated plant. In order for your plants to develop proper ears, they must be pollinated so you need to take this into consideration. Never plant your corn in a single row. Either use double-rows or short blocks of about 4 rows. You can still reach all the plants, but they will be able to pollinate each other when the wind blows. Keep the rows about a foot apart from each other.

Different varieties of corn can cross-pollinate and leave you with an unexpected harvest. This is really only a problem if you are growing very sweet varieties of corn along with “regular” corn. Keep the varieties at least 25 feet apart, or only grow one kind of corn. You can’t be positive what will happen if sweet corn gets “contaminated” with normal garden corn. Sometimes it just produces less-sweet corn, but sometimes the kernels just shrivel up and are ruined.

For very small gardens, you should be able to plant at least 8 to 10 corn plants in order to ensure decent pollination. You can pollinate by hand for small crops. See below in the Containers section for more details.

If you are going to be planting just as the temperatures are at 60F, use seed treated with fungicide to help prevent early rot. Once the soil temperature reaches 65F or higher, this won’t be as necessary.

Growing Instructions

While the plants are growing, take care to keep your corn patch as weed-free as possible. If you use a hoe, keep it fairly shallow so you don’t damage the corn’s roots just under the surface.

Keep your plants well-watered, especially once they have started to grow their ears and have sprouted their “tassels” on top. The corn kernels will start filling in, and having adequate water is vital. Water every 2 or 3 days.

Containers

It definitely can be done, but the size of the plants does make it awkward. Thankfully, the shallow root system of the corn plant helps in this case. You’ll still need containers at least 5 gallons in size (10 or more gallons would be better).

Just like in the garden, corn is wind-pollinated so plan on planting 6 to 8 plants and keep them clustered together rather than in a row. If you grow fewer plants, you’ll have to pollinate them by hand.

The pollen is produced at the top of each plant, in the male “tassel”. When it starts giving off its powdery pollen, you know its time to help with pollination. Carefully break off a piece of the tassel section, and shake some of the pollen off onto the new silks that have formed on the new female ears. You need to transfer the pollen between plants, so don’t pollinate an ear from its own tassel.

Pests and Diseases

Poorly growing corn can be the result of cool temperatures, or a lack of nutrients in the soil. Add fertilizer or additional compost to help keep your plants thriving.

Other than that, corn borers are a big problem. They will chew through the stalks of young plants, and can kill the entire plant. Pick them off if you see small worms around the base of your plants, and you can treat the plants with pyrethrin insecticides or rotenone.

You will also have to watch out for corn earworm, which attacks at the other end of the plant. Its a moth caterpillar that will eat your developing ears of corn. They start at the tips and work their way down, so you can check under the husk to see if they’ve invaded your corn. A home remedy for earworms is a few drops of mineral oil into the tips of the ears to smother the worms. It won’t harm the rest of the corn.

Harvest and Storage

How long your crop takes to develop and produce mature ears of corn will depend more on your weather than anything else. The more hot days (over 90F) you have, the faster your corn will grow. This can make it difficult to plan your harvest season, but that is one of the challenges of growing corn.

You will have to check on the developing ears to see what they are ready to be picked. Your first indication that you should take a closer look at your corn is that the silk has dried and started to turn brown. Peel back a little bit of corn husk on an ear, and use your fingernail to pop one of the kernels. It should be full with a milky liquid inside. Clear liquid inside the kernels means that you need to let it mature some more.

When picking, steady the stalk with one hand and twist the ear off with the other hand. If you just pull on it, you will likely snap the stalk and kill the plant. It may not matter if you kill the plant if you are taking all the ears off at once, but you also don’t want to disturb the other nearby plants by having one get uprooted.

Depending on your weather, you can expect 2 to 3 good-sized ears of corn per corn plant. You will get the best flavor if you only pick what you are going to use within the next day. For longer storage, cut all the kernels off the cob and freeze.