How to Grow Sweet Corn

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“Greens!” provides step-by-step principles of organic gardening along with instructive and beautiful photographs. Experienced and budding gardeners alike will find a source for inspiration in this handy guide.
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To sow the best corn possible, you should keep to one variety at a time.

You can grow your own vegetables whether you own your own home or live in an apartment. Author Karin Eliasson gives advice on growing over 100 vegetables as well as how to use them in the kitchen. In this excerpt taken from Greens! (Skyhorse Publishing, 2013) learn how to grow sweet corn, from cultivating corn to harvesting it.

You can purchase this book at the MOTHER EARTH NEWS store: Greens!.

Corn brings us to warmer shores and Mexican hats. But it is very possible to grow corn in colder climates as well. It is even pretty easy, as long as you keep in mind that corn needs a little extra warmth and shelter from the wind to feel at home. In southern and middle Sweden they cultivate a lot of sweet corn (Zea mays var. saccharata), which is the most common corn to cultivate in the garden, but it’s also a food source for animals. Self-picking is also common. Even though I’ve started to grow my own corn to secure a few well-filled plastic bags in the freezer, I can still find charm in the large corn fields. I gladly take a stroll among the tall plants now and then to experience the sensation of being lost. As a child, I would keep an eye on my mother’s legs on the row next to mine, so that the fear that I would never get out would decrease. The fields are intriguing.

Corn is definitely one of the growths I often place in the children’s garden corner. Most children like corn, no matter if they’re large corn cobs or cute mini kernels. Furthermore, the seeds are large and even small children’s hands manage to stick them in the right place. Since the corn preferably grows in large groups, you can play with the shapes when you set them out and make wavy roads between the groups. The corn (Zea mays everta) used for popcorn is especially exciting. Imagine growing your own popcorn! It is a somewhat different corn cob than the ones we are used to eating, a smaller and tightknit cob with tiny kernels. It needs a little more time to mature, so if you don’t live in a more temperate climate you should grow them in a greenhouse or start pre-cultivating early.

Since corn is one of the world’s most cultivated seeds, there is obviously a whole sea of varieties. Cultivating in the North does, however, set certain requirements that the corn cannot be too sensitive to cold and that the fruit grow early and ripen fast. It is therefore best to keep to the varieties that are already tested in your climate.

How to Grow Sweet Corn

Preparing the Growth Site

Corn is, as previously mentioned, dependent on warmth and needs a little extra attention to reap a nice harvest in colder climates. Make sure that it grows in a sheltered, sunny spot. The best way to secure warmth around the root system is to make sure that the soil is well-drained, light, and humus-rich. If the spring is particularly cold you can warm the soil with a plastic cover before sowing or planting. Fertilize the soil with manure and compost. The corn wants a lot of nutrients and water, and if you can cover cultivate with organic material, that’s ideal. Corn likes to be cross-fertilized. To sow the best corn possible, you should therefore keep to one variety at a time. Choose your variety with care and keep to one variety every year.


When?I always recommend pre-cultivating corn to win time. In southern parts of Sweden, and warmer climates, you can sow directly in the ground, but the soil temperature must be at least 60°F (15°C) and when the plant has appeared, any risk of frost must be gone. If you pre-cultivate, start four to five weeks before you plan to plant them outside, and wait until there is no chance of frost.

How?The corn quickly develops a large root system and should therefore be sown in deep root trainers. If you want to save space you can first broadcast sow the seeds in trays and then replant them when they are about 2 inches (5 cm) tall. Fill the trays with a blend of planting soil and sifted soil. Push the seeds 1–2 inches (2–4 cm) deep and makes sure that the soil is lightly packed. Water the soil properly. Let the seeds germinate and the plants appear when the temperature is about 77°F (25°C). Later you can lower the temperature somewhat when they start growing properly.

When you sow directly in the ground, the easiest way is to make a 2 inch (5 cm) deep trench in the soil and water it. Add the seeds, cover with soil, and water everything again. The corn will pollinate better and get more fruit if it grows in groups instead of rows. Make large circles or squares and sow the corn with 8–10 inches (20–25 cm) distance between each plant in every direction.

Planting Outside and Nurture

The plants are not moved outside until the risk of frost is completely over. The hardening process is very important. Have fiber cloth at hand in case there are surprising cold nights. Keep weeds away from the corn. It doesn’t like competition and cover cultivating is preferred from this perspective as well.

Support fertilize with stone meal or Algomin when it blossoms. When the corn is about to pollinate, you can help them out by gently shaking the plants a little so that the seed flour rains down on them.

Be extra vigilant with watering once the fruits have appeared. Remove side sprouts that shoot out from the base of the plant. They just steal energy, and they rarely turn into nice fruits. Let only two or three corn cobs develop on each plant unless you are cultivating a mini-corn variety. In those cases you can expect 10–15 cobs per plant. Upwards cup some dirt against the stem when the plant is about 20 inches (50 cm) tall so that it gets extra support around the base. Repeat as you go if needed.


When?Regular corn is ready for harvest at the end of summer. The threads at the top of the cob should be withered and if you carefully peel back the leaves, a light pointed push against the corn kernel should release a white corn juice. If the juice is transparent, the corn is not ready. Mini corn is harvested before the kernels develop. Open the peel and carefully peek to get a sense of how mature the corn is. Regular harvest encourages greater crops. Popping-corn should be left until the kernels are dry. After which, they should be harvested and dried even more spread out in a warm room indoors.

How?Harvest, prepare, eat. The cobs are easy to break off of the plant by hand. You should not let many minutes pass after you harvest them till they’re boiling in the pot. Corn that is left for a long while after harvest loses flavor and elasticity as the sugar transforms into starch quickly. It is also great to grill corn. If you grill them fresh you don’t have to remove the peel, just polish them and remove the threads. If you grill them peeled, maybe even slightly blanched, you may brush them with some chipotle glaze for a spicy and smoky taste. Corn is best stored in the freezer.

Read more: Check out How to Grow Beans and How to Grow Lettuce from Greens! for more tips on growing your own vegetables.

Reprinted with permission from Greens! Tips and Techniques for Growing Your Own Vegetables by Karin Eliasson and published by Skyhorse Publishing, 2013. Buy this book from our store: Greens!