Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
Corn has been grown for thousands of years and the idea of popping corn has been around for just as long. It was the Native Americans who introduced the European colonists to this treat.
What is Popcorn?
Corn (Zea mays) is actually a type of grass. It was bred in Mexico from a wild grain called teosinte. Modern day corn comes in three versions. There is sweet corn which we eat, field corn which is fed to livestock, and flint corn, also called Indian corn, which is the one that we use for popcorn.
Flint corn has very colorful kernels. No matter what color the corn kernels are, they will always pop white because the starch inside of the kernels is always white regardless of the exterior color.
Poplular varities of popcorn you can grow include Strawberry with deep red kernels, Lady Finger and Tom Thumb, a miniature corn. My personal favorite is called Glass Gem. The kernels are different colors and each ear of corn has a different combination of colors. Shucking the ears is like opening gifts. You don't know what colors you will get until you have unwrapped the entire ear.
Why Does Popcorn Pop?
A corn kernel consists of a hard outer shell which contains soft, moist starch. When heated, the moisture in the starch turns to steam and the starch expands. Eventually it becomes too large to be contained by the kernel. The hard kernel then "pops" and the starch is released. When the hot starch reaches the outside of the kernel, it cools into the familiar popcorn.
The reason that flint corn pops better than sweet corn is because sweet corn has so much moisture that the starch just boils and the kernel gets mushy rather than popping.
There are two kinds of popcorn, "snowflake" and "mushroom". The names refer to the shape of the popcorn after it pops. Snowflake popcorn is the one that comes in the bags that you microwave and is also sold at concession stands. It looks like it has arms. Mushroom popcorn is rounder like the cap of a mushroom. It is used to make caramel corn because it is not as fragile as snowflake popcorn. Most seeds sold to consumers will yield snowflake popcorn rather than mushroom popcorn.
How to Plant Popcorn
Corn is a heavy nitrogen feeder so if you are practicing crop rotation, plant your corn in an area that was previously planted with legumes such as peas and beans which are nitrogen fixing. A good alternative is planting a cover crop in the prior fall.
Wait until after all danger of frost has passed before planting your seeds. The seeds germinate best in soil that is at least 60⁰F.
If you are planting in rows, make them short and relatively close together. 12 inches apart is ideal but no more than 36 inches to ensure the best pollination. You will need a minimum of 4 rows. More is better. Plant 2 to 3 seeds per hole, 1 inch deep. Germination should occur in 12 days. If all of the seeds germinate, thin them to 12 inches apart when the plants reach 15inches tall.
If you do not have space for that many rows, you can plant in hills. Each hill should have 6 seeds which can be thinned to three when they germinate. Thin by cutting your plants off at the soil level, not pulling them which can damage the roots of the plants that you are leaving in the ground.
How To Water And Fertilize Popcorn
Corn needs a minimum of 1 inch of water per week. If the rain is not sufficient and you must supplement watering, water at the roots. Watering with a sprinkler can wash the pollen off the tassels as the water falls from overhead.
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You can add compost or fertilizer when your plants are 6 inches tall and then again when they have reached the height of your knee. Corn does not compete well with weeds, so you will need to weed frequently.
How to Pollinate Popcorn
Corn has both male and female flowers. The male flowers are the tassels at the top of the stalk. The female flowers are the silk on the ears. The silk must be completely pollinated by the tassels to produce the kernels on each ear. Incomplete pollination will result in incomplete ears.
You can help the process by hand pollinating or if you want a method requiring less effort on your part, you can just walk along the rows and shake the tassels which will release the pollen to fall on the silk in the ears.
How to Harvest and Store Popcorn
Most corn is ready to be harvested when the silk turns brown on the ears. In the case of popcorn, you want to leave the ears on the stalks as long as possible to dry them out. If possible, leave the ears on the stalks until right before your first heavy frost. The husks should be brown before you harvest.
If you are unable to leave the ears on the stalks until the husks turn brown or the weather is unusually wet, harvest your ears and bring them indoors. Turn the husks back to expose the kernels and hang them in cool, dry place until they have finished drying. The kernels are dry when you are unable to press your fingernail into them. Or you can test by trying to pop a few kernels.
When the kernels are dry, remove them from the cob by either twisting the cob until the kernels pop off or by running your thumbs down the cob causing the kernels to pop off. Keep only full sized kernels. Throw away any tiny or immature kernels. Store the dried kernels in an airtight container away from light. Properly stored, popcorn will keep for several years. If you have old popcorn that is not popping, it may be too dry. Add a little water to the container and shake periodically until the corn has absorbed it. Then try popping it again.
How to Save Popcorn Seed for Next Year
If you plan to save seed for next year, plant your popcorn in a separate garden or at least 500 feet from your sweet corn to avoid cross-pollination. Sweet corn will not yield as well nor taste as good when cross-pollinated with a popcorn variety. You can also prevent cross-pollination by bagging and hand pollinating your popcorn or by staggering your planting times so that the tassels which carry the pollen mature at different times.
As you harvest your popcorn, set aside the best ears with the best kernels to save for next year. Only save as much as you plan to use the following year because corn seed only stays viable for about a year. Germination rates plummet after the first year.
© 2014 Caren White
Caren White (author) on June 15, 2014:
Patsybell, that's a great idea! Thanks for reading.
Patsy Bell Hobson from zone 6a, Southeast Missouri, USA on June 15, 2014:
There are so many beautiful choices. It would be fun to have a field with a few of them all, just to see what does best in our area. Good information
Caren White (author) on June 15, 2014:
Peggy, I also think it would be fun to grow my own popcorn! Thanks for reading, voting, sharing and pinning.
Peggy Woods from Houston, Texas on June 15, 2014:
This is very interesting. I don't have room to grow corn of any kind where we now live, but for those who do have the room, it would be fun to grow one's own popcorn. Voted up, useful and interesting. Pinning to my gardening board and sharing with my followers.
Caren White (author) on June 15, 2014:
I agree, Jackie. I'm not growing corn now but if in the future I do, I will definitely plant some popcorn. Thanks for reading!
Jackie Lynnley from the beautiful south on June 15, 2014:
Very interesting to read though I won't be planting any it still would be fun to try. Thank you!
Caren White (author) on June 08, 2014:
Thanks, Flourish! I really enjoyed writing this hub. So glad that you found it as exciting as I did. Thanks for the pin!
FlourishAnyway from USA on June 08, 2014:
Very cool. I could see kids getting excited about this ... and adults too! Voted up and more, plus pinning.