An annual crop that has a very satisfying yield, sweet corn is one of the favorite plants of gardeners. This crop is capable of producing ears of white, bi-colored, or yellow kernels. To grow corn, a frost-free and long growing season is essential.
Learn more about the basics of planting, growing, and harvesting corn in your garden through this article.
Quick Facts About Sweet Corn
- Botanical name: Zea mays
- Type of plant: Annual, vegetable
- Soil type and pH: Loamy; acidic to neutral (around 6.0 to 7.0 pH level)
- Sun exposure: Full sun
- Flower color: Yellow and white
- Bloom time: Summer
- Mature size: 6 – 8 feet tall, 1 – 2 feet wide
- Hardiness zones: USDA 2 to 11
- Native Area: Mexico
Sweet Corn Defined
Sweet corn refers to a specialty maize species, which is genetically different from field maize. It comes with delicious and tender kernels that are also being consumed as a vegetable in several cuisines in the world.
Also called pole corn and sugar corn, it has a higher amount of sugar compared to the other corn varieties. It also results from the naturally occurring recessive mutation within the genes that work in controlling the process of converting sugar to starch within the corn kernel’s endosperm.
Unlike the traditional field corn, the crops of sweet corn have to be converted while the corn-ears just attained the milky phase. You may use the cob immediately or freeze it to use later since the sugar it has can rapidly turn into starch.
Sweet Corn Versus the Traditional Corn
Is planting and growing sweet corn different from growing traditional corn? Well, the major difference between the two is the taste. Note that what people know as field corn comes with a bit harder cob and a starchier taste.
Meanwhile, sweet corn is different in the sense that its taste is pleasantly sweet. It is also softer compared to traditional corn.
In terms of the corn planting process, the one for sweet corn is quite easy. It is not that different from the process of growing traditional corn. You have to practice proper corn planting for it to grow healthily the entire summer, making it possible for you to eat fresh corn on cobs soon enough.
Common Varieties of Sweet Corn Plants
Hybrid corn comes in four primary types or categories. These varieties or types of corn are categorized depending on their genetics and sugar content. The categories, therefore, are used to determine the sweetness of the variety, which you can often see directly on the seed packet.
You have to know exactly what corn seed plants you should consider planting not just because of their sugar but also because of the level of ease when it comes to cross-pollination. If the ones that underwent cross-pollination are of incorrect combination, then there is a high chance for the produced ears to be of poor or subpar quality.
This is one of the sweet corn varieties considered as classic. The su variety tends to grow vigorously while being recognized for its stress-resistant nature. Expect the kernels here to be not too sweet, even having the traditional taste in most cases.
However, note that the sugars in this variety tend to turn to starch fast after picking the ears. That said, it is crucial to eat them directly after picking. Avoid planting the su variety close to synergistic or shrunken types.
The sugary-enhanced type often has a slightly sweeter taste compared to the sugary versions. Expect this sugary-enhanced (se) variety to retain its sweet taste for a much longer time after harvest compared to the sugar varieties.
Shrunken (Sh, sh2)
Shrunken (sh, sh2), otherwise known as super sweet, are known as the sweetest out of the several different varieties. This super sweet variety has twice or thrice more sugar content compared to the sugary types.
You will also notice the sugar content of the sh2 kernels lasting longer (even up to one week) after harvest compared to other kinds. What makes it even more different is the crunchier texture of the kernels. The taste is also not as corny compared to the others.
The shrunken (sh2) is also more of the choosy type. Avoid planting it close to other types of corn as hybrid kernels tend to come out tough and starchy.
The sy variety is a combination of sugar-enhanced (se) and another of the other sweet corn varieties. This results in varieties that tend to have the best of the different types. Expect the synergistic variety to produce tender and sweet kernels that taste good.
You can also expect some of the sy varieties to keep up until one week after you harvested them. Just make sure to avoid planting corn seed close to the shrunken or sugary type to ensure that it will truly have favorable yields.
The Ideal Site for the Healthy Growth of Sweet Corn
One important fact about sweet corn is that it is quite picky when it comes to the soil. Ideally, you need to work compost or aged manure into the soil where you intend to plant it in the fall. It is also crucial to let it overwinter while it is in the soil.
As soon as the spring season comes, you can expect the soil to be fertile, making it ready to receive the corn. You may also just mix in aged compost with the soil before planting.
The perfect soil is one that is well-draining while still having the ability to hold enough moisture. The reason is that sweet corn needs water for it to grow properly.
To cross-pollinate adequately and successfully, make sure to plant the plot correctly. Rather than planting one to two long rows composed of sweet corn, plant blocks of it with a minimum of four rows deep. With that, you have an assurance that the corn pollinated by the wind can produce viable and full ears.
Another thing to remember is that while corn can tolerate all types of soil, it will still be in favor of well-drained soils that have a pH level of around 6 to 7.0. Try to avoid sandy soils as much as possible as well as soils that have a low pH as those may only cause the plant to deal with magnesium deficiency.
Planting and Cultivating
One fact about sweet corn you should know before planting it is that it does not seem to transplant well when you are using seedlings – that is unless you use a biodegradable pot. That said, one of the most effective planting methods is direct seeding. Do this once the threats and dangers of frost already passed.
The fact that this specific corn is wind pollinated also means that it is ideal to plant it in blocks instead of rows. Pollen derived from male tassels also has to come in contact with female silks. Planting corn close together means that they will be more in contact.
It is also highly likely for wind pollination to promote ease when it comes to cross-pollination. That said, make it a habit to separate various kinds of corn. They should be around 25 feet apart at the very least. Alternatively, you can separate varieties that have different maturity times.
Make it a point to plant seeds with a depth of around 1 and ½ to 2 inches. The spacing should also be 4 to 6 inches apart. Provide the seeds with sufficient water afterward.
As for the size, note that it tends to differ based on the type or variety you decided to grow. It will also differ based on the growing conditions. Most of them, however, still grow at an average size of 6 to 8 feet tall. You can also grow shorter varieties if your garden only has limited space.
Also, note that while you can easily plant corn in sunny and warm gardens, bringing their fruit for a successful harvest may be quite challenging. The reason is that you will have to compete with squirrels, raccoons, crows, and a lot of other pests who may also feed with the sweet corn.
That said, make sure that you harvest the sweet corn in a timely manner to prevent other animals and pests from infesting them.
Caring for the Sweet Corn Plant
To ensure that your sweet corn will remain productive and healthy, make sure that you are able to provide the following:
For the different types of sweet corn to achieve nice and healthy growth, you need to plant it in an area that allows it to gain full sun. This will ensure that all its ears will be filled out.
Also, note that since this plant does not come with a deep root system, it is crucial to cultivate it in an area with full sun while being sheltered and protected from the wind. The reason is that strong winds will immediately flatten the corn.
The right soil is also necessary for growing different varieties of sweet corn. The best choice is a loose and loamy one that has a neutral pH level of around 6.0 to 7.0.
To make the soil even better for their growth, it is advisable to amend it before you sow seeds. Start with the help of a garden tiller, which is useful in breaking up the area once you start to plant corn.
In case the soil is too hard, put on a few passes through it until it has loosened sufficiently. After that, you can integrate the first round or layer of composted manure or topsoil. Use a rake to spread it until it has been distributed evenly.
It is also necessary to water them regularly. This is especially true once its leaves begin to curl. Another sign that it needs watering is when its cobs start swelling.
It would be best for you to water the plant deeply once every week, instead of supplying it with only a bit of water every day. Free this area with weeds as those may also compete for water and food, leaving only a little for your sweet corn.
If you make use of sandy soil, then note that it is highly recommended to water more frequently than one time every week. One inch of water is capable of wetting sandy soil up to 10-inch deep. If you are using heavy clay, then such an amount of water can give it around 6-inch deep.
With the help of a trowel, you should also assess how wet the water in the soil is as far as depth is concerned. If there is only one to two-inch depth, allow the water to continue running.
A lot of garden plants can also be expected to stop their active growth phase once the temperatures go over 85 degrees F. As for the corn, you have an assurance that it will continue growing even when the weather is hot.
However, take note that it will also become drought-stressed during dry and hot spells due to lack of irrigation. One more thing to remember is that the depth of the sweet corn’s rooting is kind of shallow.
That said, despite the fact that it has several newly developed roots over the soil (as you will be able to see in the plant’s base), such roots will be incapable of absorbing plenty of nutrients and water. The main goal of these roots, instead, would be to keep the plant stable.
Humidity and Temperature
When it comes to soil temperature, it would be better to stick to 60 to 65 degrees F. If that temperature is not adhered to, there is a high chance for the seeds to not germinate properly.
During cold climates, make it a point to use black plastic as a means of covering the soil beforehand. This should help in quickly warming the soil.
It is also crucial to note that sweet corn can be considered a heavy feeder. With that in mind, it definitely requires rich soil. Nitrogen is specifically vital in this case as corn, basically, is grass.
One to two inches of rotted manure or compost can also be expected to work. The same results will be provided if you feed your plant with fish emulsion.
Another thing that you can do to nourish the plant is to put on nitrogen fertilizer. Do this once the sweet corn reaches around 8-inch tall. You should also apply this type of fertilizer as soon as the pant begins to produce tassels.
How to Control the Weeds?
One of the problems you may encounter when growing sweet corn is the presence of weeds. The problem with these weeds is that if left uncontrolled, they will compete with the nourishment and water that’s supposed to be for the sweet corn.
This is the reason why you have to make it part of your routine to monitor the area for the presence of weeds and control them. In that case, use a hoe or any other tool that will promote shallow and frequent cultivation. That way, you have a better chance of dealing with and killing all the weeds before they cause problems.
When it comes to using the hoe, make sure to do the hoeing with just enough depth for cutting off the weeds beneath the soil’s surface. Be extra careful so you can avoid causing damage to the plants during cultivation, too.
Once already established, expect them to create a group of leaves capable of discouraging the growth of new weeds. Also, if you decide to use herbicides in killing the weeds, avoid using them close to the sweet corn. The reason is that these herbicides may only cause further damage to the plants.
Harvesting and Storing the Sweet Corn
One sign that the sweet corn is already ready for harvest is when you see the kernels at the ear’s center becoming milky and full when you squeeze it. Expect the silks to dry out and become brown when it is already time to harvest.
This should occur 18 to 24 days immediately after you notice the silk becoming visible for the first time. Such a time also differs depending on the weather condition.
To harvest, just pull down the ears then twist them off to remove the stalk. If you are growing the sugary (su) varieties, then note that they will start losing their sweet flavor right after harvesting so it helps to make use of them right away.
Prepare to eat or preserve them right after you pick them. One more thing to remember is that depending on genetics, it is highly likely for the freshly harvested corn to retain its overall quality for at least 7 days provided you put it in the fridge.
Another storage technique is to can it. Note, though, that canning this harvest is only possible if you process it with the aid of a pressure canner. Freezing is also an effective way to store and preserve the harvested sweet corn.
This plant has small amounts of several vitamins and minerals. That said, it would be best for you to cook it right after picking. Cook it on or off the cob.
Make sure to remove the silks, husks, and any other bad spots before cooking. Also, note that even corn that is already quite beyond their best quality is still great when prepared and served in cream-style form.
Generally, sweet corn is devoid of any serious disease. However, you still have to watch out for the following so you can control them and deal with them as soon as they appear.
This specific disease may trigger the development of firm and tumor-like growths on the tassels, stems, ears, and leaves. Find smut galls during the entire season then cut them before spore production.
Take out the galls from your garden then bury them. Avoid composting them. The smut may also cause gray-black mass to appear on the ears. In that case, you can control it by cutting off the ear that’s affected by the problem then disposing of it.
There is also a chance for this plant to develop leaf rust. This one comes in the form of rusty orange streaks that are visible on the plant’s leaves. They can release a substantial amount of powdery orange spores.
The best way to avoid dealing with this issue in the first place is to plant only those rust-resistance varieties.
Gray Leaf Spot
A gray leaf spot is a form of fungal infection that may appear on the leaves as tan lesions. It is highly likely for them to come out around two weeks prior to the corn’s production of tassels. If you don’t treat it, there is a chance for the lesions to not only turn brown but also grow bigger and merge, which may kill the whole leaves.
Pests to Manage
Aside from the diseases that you have to watch out for, you also need to observe this corn constantly to determine if there is any pest infestation. Note that just like other plants, sweet corn is also more prone to getting infested with pests.
Check your crop daily to control such problems right away – the most common of which are:
Two kinds of aphids that may infest your sweet corn are the greenish-yellow green peach and the blue-green leaf aphids. The problem with these pests is that if left uncontrolled, they may cause stunted growth.
The reason is that these aphids will sack sap from the plant’s leaves, leaving honeydew, a sticky substance that may cause sooty mold to come out. One thing to note about aphids is that they like weeds so much. That said, it is important to remove weeds from your garden to prevent aphids from developing, too.
You can also eliminate aphids from the sweet corn, and perhaps your entire home garden, by blasting water to it using your hose. This should help in knocking the aphids off. You should follow this with the spraying of neem oil on every plant as a means of discouraging re-infestations.
There are also what we call cutworms that refer to gray-brown worms that serve as seedling decapitators. These cutworms tend to cut seedlings away from their life source, specifically the root systems.
To drive cutworms away, create a tinfoil necklace designed for every plant. Put it around the stem of your plant. Examine this collar daily to determine if a cutworm is present. This also helps ensure that the stem does not rot.
Take off the collar prior to watering then have it replaced after one hour or so. This is necessary for making the plant breathe. Take out the collar upon seeing the seedlings starting to grow into young yet strong plants that have thick stalks.
European Corn Borer
This refers to a whitish caterpillar, which is capable of attacking the plant’s tassels. This can result in their stalks snapping off.
The European corn borer also tends to hollow out the stalk by eating and munching the stems and cob shafts. This can lead to them falling off from the mother stalk.
One more thing that this whitish caterpillar does annoyingly is nibbling on the kernels that are still developing.
You can deal with and control this infestation with the help of a microbial pesticide. Just make sure to choose a non-toxic and organic one as much as possible.
Frequently Asked Questions (FAQs)
How long does sweet corn take to grow?
The length of time it would take to grow sweet corn will depend on the specific variety. Some super-sweet hybrids tend to mature within just 60 days. Other varieties take up to 100 days to mature.
If what you decided to grow and cultivate is field corn for animal feed or popcorn designed for snacking in the winter, then expect them to mature at around 100 to 120 days.
How do you grow sweet corn in the UK?
Sweet corn is a plant that you can grow anywhere, even in the UK. Like other plants, you just have to supply them with the things they specifically need, including a sunny, sheltered, and warm spot protected from the harsh and strong winds.
The soil should also be fertile. Preferably, you should use heavy or dry soil, too. Make sure that the ground is ready by digging plenty of well-rotted manure or compost designed for the garden.
Is sweet corn hard to grow?
No, it is not hard to grow sweet corn at all. It is even possible to grow it everywhere provided you have everything that it needs for healthy growth. It is also important to water this plant sufficiently.
How much corn do you get from one plant?
Provided the corn plant receives sufficient growing conditions, it is capable of producing around two to four ears of corn.
Earlier variations can produce fewer than that while those that mature late can be expected to produce a bit more. Also, the number of corns you specifically get from a single plant will greatly depend on the way you care for it.
Should you weed the soil regularly?
Yes, you need to remove all the weeds from the soil. Make it a habit to remove the weeds. If you see that there are new weeds, pull them up right away.
Do the pulling by the roots, resulting in the clearing of the area. Keep in mind that these weeds tend to drain the soil and take all the nutrients needed by the corn to grow. Just exercise caution when weeding so you can avoid pulling up the plant’s shallow roots.
Overall, sweet corn plants are popular crops and vegetables that you can easily grow. Making it a part of your garden is definitely very satisfying especially if you want to have easy access to these crops.