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.

14 Responses to “How to Grow Corn”

Diane Childers Says:
August 5th, 2010 at 6:31 pm
Problem: This is the second year in a row I have grown corn in a large garden in OH. Both last year and this year I have beautiful tall corn stalks but I have a problem with the corn cobs. For some reason my corn cobs are mini cobs and will not grow to a normal size corn cob. Have you ever heard of this happening? If so do you have any idea what the problem/issue could be? Any help or tips would be greatly appreciated -Thank You.
R. Mills Says:
November 3rd, 2010 at 6:46 am
I am thinking that you need a heavy dose of fertilizer. Corn plants really suck all the nutrients out of the land. This being the second year you used this garden for corn will leave the soil lacking the sufficeint nutrients. Also, Does it receive a full amount of sun daily ?
Ashley Freeland Says:
August 16th, 2011 at 1:51 pm
hello,
can you eat corn that has earworm?
thank you,
ashley
Warren Jones Says:
December 21st, 2011 at 11:52 am
I first planted my corn on September the 15th. However, because of problems with my corn (death), I planted more a week later, then a week or ten days after that. I had no more problems after the third planting, and my patch looks great. However, I do have one problem: no ears yet. One stalk has a developing tassel, but there are no signs of developing ears. It looks like my corn will not be developing ears, and I’m wondering why. What are some of the common reasons for this? Incidentally, I should mention that I got a late start this year. I planted my corn about a week after the close of the planting season. Other than that, I can think of nothing unusual. No pests, no disease, and no unusual weather. The only thing I can think of is water. The corn is growing in raised self-watering beds, and from probing the soil, I know that there is enough water: feel, abundant earthworms, etc. Also, the plants are a verdant green and very healthy in appearance. I was going to say that maybe I have been overwatering, but wouldn’t there be signs of this? Doesn’t overwatering tend to produce yellow leaves? Oh, one last thing, I have taken care to check on the nutrients. I know that soil testing kits are not very reliable, but what else can I do? I used them if that’s not clear.
Addem: One tiny ear started appearing two days ago, but I have 24 corn plants in my corn patch. [This situation continues as of 12/21/11]
Jeffrey N Says:
July 13th, 2012 at 6:48 pm
I have tassels now. How long before I will see the ears.
Ann Bullock Says:
August 4th, 2012 at 3:57 pm
A bird or critter must’ve dropped ONE seed of corn behind my condo building and a corn plant began growing. Just for the heck of it and to see how big it might get, I’ve been watering it when I water the plants on my patio… the stalk is now about 5′ 6″ tall and has sprouted tassels at the top. Since this is the ONLY corn plant around, will it ever make an ear of corn? I’m NOT expecting to eat any of it; besides, the squirrels will probably beat me to it… IF any ears form.
Jeannie Says:
August 23rd, 2012 at 9:35 pm
My sweet corn is tall & a beautiful green color, it has tassels, some getting heavy with pollen, but NO sign of ears forming & of course no silk. I have kept the corn patch well watered,& used an 8-8-10 fertilizer, working it well into the soil. I’m desparate!! Autumn is just around the corner here in the Pacific NW. Help me PLEASE!!!
-Stymied-
Administrator Says:
September 25th, 2012 at 5:20 pm
The chances of you getting a full ear are slim, it is also likely field corn, not sweet corn, so you wouldn’t want to eat it… but you can help pollinate by brushing the flower tops on the silks coming out of the ears.
David M Gosselin Says:
September 25th, 2012 at 8:43 pm
Can I make corn seed from an ear of corn bought from a road side stand? How can you tell if an ear of corn is or has been cross pollinated or from a hybrid? If I can make a corn seed from an ear already picked how do I make it into a plant-able seed? Thanks.

Respectfully,
David M Gosselin
(new to gardening)
Alesha Says:
June 1st, 2013 at 12:08 pm
I have suckers at the base of my corn, in my backyard garden. I’ve pulled them off and I was wondering if I could replant them, like I do with tomato suckers. Thanks in advance for your advise.
David Johnson Says:
August 30th, 2013 at 2:44 pm
My corn has ants and aphids. Is the corn safe to eat?

Thanks
Pam Hickey Says:
June 20th, 2014 at 9:17 am
If you have suckers at the base of your corn its usually a phosphorus deficency. Bone meal will fix it. I use a large screwdriver to drill a hole beside the stalk about 6″ deep and fill it with bone meal, then water it in. Takes a while but it works like a charm. If you see purple streaks as well as deformed stalks, again, the bone meal will help. After years of trying to grow corn here in NC, I’ve finally got a decent crop going LOL. Lots of research last year.
John Olynyk Says:
August 8th, 2016 at 11:06 am
I have heard that once cobs start forming, that if you break or bend the stalks at the top, I will get bigger cobs. Is this true or is it a fallacy?
thanks
Administrator Says:
September 22nd, 2016 at 3:13 pm
I can’t imagine that is true, the stalk is the path of nutrients to the cob.