I grow corn and have become quite good at it. Here are my best tips for growing, harvesting, and storing corn!
When grown and harvested correctly, I don't think there's food that tastes better than sweet corn in the summer months—or any time for that matter. I also believe it's the most anticipated crop grown by the majority of gardeners who wait for that first bite of sugary sweet corn to devour.
Beginners or someone who does not pay too close attention should not buy what most of us call "field corn." This is especially true when buying corn seed from a feed store and not a packet. Field corn is specifically designed to feed animals, and it has little or no sweetness to it at all.
Also when acquiring sweet corn from a local farmer or market, be sure to let them know it's for you and not an animal you have. Most farmers will of course ask you what you want corn for, but I've known more than one person who has bought corn thinking it's sweet corn, and it's anything but.
In this article, we'll be discussing planting, growing, and eating our own corn from the garden. Other than making sure that you get the right seed variety for your purpose, there is little else to be concerned with.
Purpose for Growing Sweet Corn
It may not be obvious to many gardeners who haven't had a lot of experience with growing corn, but when growing for human consumption, there is more than one purpose for growing it. Knowing what they are will determine the variety of corn seed you decide on. You may even buy more than one variety for those different purposes.
Don't worry. It's not that complicated. You're either going to grow corn for harvesting and eating as soon as they're ready, or you're going to grow corn to resell it. You can take the same corn you usually want to eat immediately and freeze it as well.
We won't get much into the type of corn that must be used if it is to be harvested by mechanical means, shipped, or stored. It's identifiable by supersweet (Sh2). Just look it up under that name if you want further information.
As for the two other main types of corn, they're going to be called either normal sugary (SU) or sugary enhancer (SE). Both varieties are great for growing in home gardens, with corn with the SE gene enhancer in it being far superior to corn with the SU gene.
For those of us who eat corn on the cob during the summer, the way we know which is which is by past experience. The SU corn must be cooked and eaten as quickly as possible after being harvested because the sugar content, and thus the sweet taste, will leave the corn quickly. Don't wait for more than a couple of days to cook and eat this corn. To get the absolutely best experience, eat it almost immediately.
If you're going to freeze the corn, use the same best practices. Begin processing it as quickly as possible to retain the most sugar and sweet taste.
Corn with SE Gene
Corn with the SE gene has an even higher sugar content, which can lend itself to keeping its sweetness a little longer than the SU corn.
SE would probably be considered more of a gourmet type, as the flavor can't be matched by any other corn. Period!
The kernels of this particular corn will be creamy and very tender, even in comparison to the good SU variety.
Both of these types can be grown side by side and don't need to be separated like those with the Sh2 gene would need to be.
There are four basic colors that corn can be grown in: yellow, white, yellow and white, and black.
One of the more popular black corn plants, which technically could be called blue and black, or even purple and black, is the Black Aztec. People use this for making blue cornmeal.
You also see these types dried and used during Halloween season for decorative purposes.
There are of course numerous varieties of corn colors because each kernel has an individual gene, even though they reside on the same cob. These multi-colored decorative corn specimens are also used during the fall season.
Although you can eat black and other colored corn, at this time they're not too tasty, although efforts are being made to produce colored sweet corn.
Most edible corn for humans, as far as on the cob or processes, will be yellow, white, or a yellow and white combination.
When to Plant Sweet Corn
When you should plant sweet corn is determined by whether you have standard sweet corn or the supersweet corn.
For standard corn (SU mentioned above), it can be sowed before the other corn, as it needs soil temperatures to be at 55°F or higher. For supersweet or SE corn, soil temperatures need to be at around 65°F for best results.
If you want to plant some real early standard sweet corn, sowing it right before the average last frost date will work. If you use some type of protection to warm the soil, it can be planted even a little earlier.
There are two planting strategies you can use to ensure you have corn throughout the summer and early fall months.
The first would be to use the same variety and stagger plant it over time. A rule of thumb would be to plant the second and successive grouping once the prior corn that was planted grows from three or four leaves.
A second way to do it would be to choose several varieties with staggered times until they reach maturity.
Some varieties, like Earlivee, will be ready to harvest as soon as 58 days, while a white corn like Silver Queen will take about 92 days to reach harvest. There are numerous other corn varieties between the disparate harvest time frames.
How to Plant Sweet Corn
Plant your sweet corn about 1/2" deep when the soil is moist and cool, and about 1" to 1 1/2" when the soil is warmer. If you're unsure, go about halfway down the first joint of your finger when pressing the seed in the ground for cooler, moist conditions, and all the way to the first joint or a little deeper with the warmer condition. If you have tiny fingers, compensate by going a little deeper than mentioned above.
Another trick to consider would be to plant about 2 to 3 seeds in each hill or spot, as that almost guarantees at least one will come up. Just thin if more than one appears, leaving the stronger of them in the ground.
Corn should have at least 30" between rows, and up to 36". There's no need to go any wider than that.
Corn and Cross Pollination
In most situations sweet corn needs to be protected from cross-pollination from other corn types.
Earlier I mentioned you have no need to separate sweet and supersweet varieties, but there needs to be a caveat to that: that's assuming they pollinate at different times. If both varieties have the same or similar pollination time, and you're not planting them at intervals, you'll want to separate them or the supersweet variety will lose a lot of its sweetness by the effects of the normal sweet corn variety.
If they pollinate at different times, this won't be an issue, and they can be planted together. In other words, if a normal sweet corn variety pollinates in about 60 days, and a supersweet in 80 days, they won't detrimentally have an effect on one another.
As for yellow or white sweet corn, other than how the corn looks, it's not relevant to the sweetness quality if they are cross-pollinated. That's of course assuming they're the same type and not sweet or supersweet with different colors.
Corn doesn't have a deep root system, so shallow cultivation is called for in order to manage weeds. The earlier and more consistently you do this, the less problems you'll have as the season goes on.
While corn can take the heat in most situations, watch the water conditions, especially in the major growing periods of tassels, silking and as the ears mature. Be sure to water the corn, or watch how much rainwater the corn is getting during this time. If water is deficient during those three key periods of growth, it will result in a poor quality of corn, with small ears, bad tips, and kernels missing.
We've all seen corn like this, and when we're doing the growing, it's not enough water that brings about these results.
Corn are notorious energy hogs, and need a lot of feeding. They mostly need a good shot of nitrogen fertilizer off and on while they grow, starting when they reach a height of about a foot to 18" tall.
Even though some sweet corn varieties will grow side shoots, it's largely a waste of time to get rid of them, as yields aren't affected by them.
If you grow sweet corn there will eventually come the time when you'll encounter one of the worst pests of corn: the corn earworm.
In some regions where the corn earworm doesn't overwinter, some corn won't be infested if they're of the early corn plantings. Corn with longer maturing dates or which is planted later will usually have some earworm infestation of some type and degree.
No matter what methods of pest control you use, once the earworm is in the husk, there is nothing you can to do stop it from being damaged, although you can limit damage, especially in a home garden.
The best method there is by taking mineral oil and inserting it into the silk. Use about 1/2 dropper full on each ear.
If you're not selling the corn, you may find some of these worms near the end of the ear, but that can easily be cut off, salvaging most of it.
Preventing Corn Earworms
As mentioned above, planting corn earlier is one major way to combat earworm infestation.
You could also use pheromone traps to attract the moths. Planting corn with a tight-fitting shuck is another practice that reduces earworm infestation and damage.
Because insecticides used in one state may not be allowed in others, it's impossible to present those solutions in general. Check your state for what's allowed and its proper usage.
Finally, a rather labor-free solution is in deciding to use Bt sweet corn, which has been genetically altered to kill earworms and other caterpillar types.
But even with that as a safeguard, if you plant corn too late you could still get some infestation and damage.
The good news is you will never find more than one earworm in an ear of corn because the dominant earworm will eat the rest because of being cannibalistic.
Your best protection against the corn earworm is to plant your corn as quickly as you're able to.
When it's time to harvest your corn, each stalk should have a minimum of one good-sized ear on it, with a second, and even sometimes a third, with some corn; although each successive ear will be a little smaller than the prior one.
Under most conditions two ears are the norm for corn grown the right way and under optimal conditions. Even so, I have more than once seen corn produce three ears on a number of stalks. Just don't expect it or be disappointed if it doesn't happen. Producing one good corn ear per stalk will be great for the majority of gardeners.
If you see a second ear, allow it a little more time to grow, as development is usually behind the larger ear, so it could and should grow a little more. Just watch it for clues as to when it's ready.
Using best practices will usually result in that second ear growing, and some luck with insects and disease. Weeding, watering and fertilizing is something that we have control over, so the more we pay attention to those the better results we'll get.
Picking Sweet Corn
The way to determine when the optimal time to pick sweet corn is is by checking out the kernels to see if they're producing what most of us that grow corn call the "milk stage."
You discover if they are in that stage by simply pressing a nail into a kernal and see what happens. If it appears milky when the juice comes out of it, it's ready for harvest. When the corn juice is more watery than milky, it's too soon to harvest.
A way you can know when it's very close to that stage is to keep track of when you first observed the first silk strands appearing. It takes approximately 20 days from that time before the corn reaches the harvest stage.
You want them to be formed completely and plump in looks, but not growing to the point of being totally mature. What you're looking for is to be sure they don't get that soft, somewhat doughy feel to them.
Once sweet corn enters the milk stage, it won't last even a week, so you do have to check the corn frequently to be sure you don't allow it to overly mature.
A secondary way to know the time is arriving to harvest is when the silks of the plant start to brown and dry out. The tips filling out and firm ears on corn that hasn't been husked yet are other things to watch for.
When the corn is ready to harvest, just grab the ear of corn with your hand and snap it off while pushing downward quickly with force.
Corn Harvest Aftercare
Once you harvest your corn, you should either eat it as quickly as you can, or refrigerate or process it very soon.
Even though the supersweet corn may last a little longer in sweetness than normal sweet corn, because of the warm time of the year it is ready to harvest, the sugar content will quickly drop while the starch content will increase.
Normal sweet corn needs to be eaten as soon as possible, while the supersweet corn has a little more leeway. But either way, the sooner you eat either variety, the better tasting it will be. The same with processing or storing.
Whatever you do, don't husk the corn until you're ready to do with it whatever you grew it for.
There you have an overall look at successfully planting delicious sweet corn.
You do have to watch them carefully as they grow, and cultivate shallowly on a consistent basis as they grow. At the right time you must also be sure they are getting enough water, as mentioned above. It's not that difficult, and work comes in spurts.
But when you bite into that first sweet corn taken off the plant and quickly cooked, you'll quickly forget about what it took to reach that point, and swear you're experiencing a little bit of heaven on earth.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Sheila Brown from Southern Oklahoma on March 17, 2012:
Wonderful information! We tried growing sweet corn several years ago. We had such an earworm problem, we gave up after 2 years. We LOVE sweet corn and we may have to try this again, using your information. Bookmarking this, voted up, useful and sharing on my blog! Thanks so much for this great information. Have a wonderful day! :)