Seed to Seed Guide: Corn
Despite the fact we live in an area still referred to as The Corn Belt by various people, corn is rarely grown in urban or suburban home gardens anymore. This is a shame because fresh out of the garden sweet corn or jeweled multicolor dried popcorn is one of life’s sweetest joys. Plus your neighbors will be very impressed.
A native to South and Central America, much like other food and garden staples like tomatoes, peppers, and pumpkins, wild corn underwent a drastic change during domestication due to millennia of carefully selected breeding by various indigenous peoples, including the Maya and the Aztecs, from a single grass-like plant with a few scattered seeds to the huge cobs and large collection of varieties we know today.
Corn has a large variety of uses, depending upon the variety or stage of harvest. Dry or “dent” corn can be ground into meal for things like cornbread, tortillas, and grits, or left whole and treated with lye in a process called nixtamalization to make hominy. Sweet corn can be boiled or grilled and eaten right off the cob, or the kernels can be cut off to be added into salads, soups, and soups or frozen to enjoy fresh summer flavors in the depths of winter. And of course, homemade popcorn can be popped for a delicious movie night treat or simply as a healthy and filling afternoon (or midnight) snack.
Seed Starting:
Corn does not take kindly to being disturbed once it has sprouted, so it’s best to direct seed them when the soil has warmed to about 60℉/16℃. In Minnesota, this means you should wait to plant your kernels until mid to late May or even early June, as corn planted in colder temperatures might rot before it has the chance to germinate. You can cover your soil with black plastic in order to speed up the warming of the ground and remove it to plant once the ideal temperature has been reached.
Prepare the garden bed in a warm spot that gets full sun. Make sure to mix in lots of organic material like compost and/or manure to provide your corn with all the nutrients it will need to grow.
Plant your kernels in rows 18 to 24 inches apart, with at least 8 inches between each kernel in a row. If you have heavy, clay-based soil, you should plant your kernels about an inch deep in the soil, if your soil is sandy, that depth should be more like 2 inches to ensure the roots are secure enough to support the weight of the mature plant above it.
Cover the seeds with the remaining soil and water thoroughly, making sure the water reaches the depth of the seeds to soak them and jumpstart germination. Sprouting can take anywhere from 10 to 24 days, depending on the soil temperature. Be patient.
Ongoing Care:
Corn needs need moist soil in order to grow optimally. You should be watering your con deeply at least once a week if it is not raining, and more often as the days get hotter and drier as the dog days of summer approach.
Corn will need help competing with weeds as they grow, due to their tendency to grow upward, rather than outward. You will need to weed them regularly to avoid them being choked out by weeds. Use a hand hoe, rake, or your hands to weed when the corn is still small, once they are about 2-3 feet tall we recommend spreading 3-4 inches of mulch; either straw, grass clippings, woodchips or dead leaves in order to minimize time spent weeding.
How you determine when your corn is ready to harvest depends upon the variety you are growing. As a general rule of thumb; Sweet corn is ready to harvest when the kennels in the middle of the ear are plump and release a milky liquid when squeezed, about 18-24 days after the tasseled tops of the cob, or “silks” appear. Popcorn and Dent corn are left on the stalk to fully mature and dry completely before harvesting. Once the ears have fully filled out and matured, you can stop watering to speed up the drying process. Ready-to-harvest kernels should be hard and shiny and have dry papery husks. If rain threatens during the drying process, you can remove the cobs and bring them inside to hang them up to finish drying, either in mesh bags or by braiding the husks together to hang them that way.
A note on Popcorn; While drying the kernels is important for proper maturing and rot prevention, if popcorn kernels get too dry, they won’t cook up correctly. During the drying process, collect about 15-20 kernels of corn each week and pop them to determine if the whole crop is ready for harvest. If the kernels cook up crisp and fluffy, congratulations, it’s time to harvest the whole crop! If they are chewy or tough, with hard edges, they are not quite ready yet, and you can let them dry out for another week before testing again. Once ready, store your popcorn in an airtight container to prevent further drying.
If you are up for a fun experiment or simply want to take advantage of a cool quirk of plant physiology, try growing your beans using the Three Sisters method. The Three Sisters method is the English translation of an Indigenous farming practice that was common for millennia before and after the arrival of European settlers. It consists of planting corn, beans, and squash together in a bed in order to take advantage of each of their unique traits. The corn is planted first and acts as a trellis for the growing beans. The beans are next and fix nutrients like nitrogen into the soil for the mineral-hungry corn. Squash is planted last, and her sprawling vines and wide leaves spread out across the surface of the soil, acting as a living mulch to retain moisture and decrease weed competition. This method can also help you save room if you have a small garden, as you will be able to harvest three different plants from a single integrated bed.
Seed Saving:
Saving Corn is pretty easy, but be aware you have to allow for ½ a mile to a 1 mile of separation between different varieties to avoid cross-pollination
Let your corn cobs fully mature and dry on the stalk. The corn is ready to be harvested when the husk is brown and papery to the touch and when the seeds inside are hard and dent slightly inward at the center. If rain or frost is a threat, you can remove the cobs from the stalk and let them hang upside down to dry in a warm, well-ventilated area.
Peel away the husk and any remaining silk from the cob and separate the kernels from the cob. Most people do this by simply putting on a clean gardening glove and stripping the kernels from the cob by hand. Separate any remaining vegetative matter from the kennels.
Place the kernels in an envelope labeled with the date and variety, and place them in a sealed, airtight container, like a mason jar. Store in a cool, dry place in your house, like a basement or a pantry. In ideal conditions, kernels can last from 6 months up to a year.
Check out these sources from the University of Minnesota, SFGATE, and Native Seeds Search for more information:
https://extension.umn.edu/vegetables/growing-sweet-corn
https://extension.umn.edu/vegetables/growing-popcorn
https://homeguides.sfgate.com/save-sweet-corn-plant-next-year-56636.html and
https://www.nativeseeds.org/blogs/blog-news/how-to-grow-a-three-sisters-garden
For starting with seeds and saving seeds check out our Youtube channel under growing resources for 2023!
What kinds of Corn are you growing? Share with us on our Instagram or Facebook at Como Community Seed Library!