How to Grow Corn from Seed
Backyard Sweet Corn
Common Corn Abbreviations
Normal, or regular sweet corn
Backyard Corn Basics
Corn is both surprisingly easy and incredibly frustrating to grow in a backyard garden. It is a crop that holds the promise of great rewards, but is subject to the whims of weather, animals, and gardener's folly.
First, the basics:
- Corn is a heavy feeder. You must keep it consistently fed throughout the growing season.
- Corn is absolutely not drought tolerant. It needs regular watering, especially while the ears are filling out
- Corn is wind-pollinated. It must be planted in blocks to maximize pollination. If you're planting a small block of corn, you may need to help the pollination effort along manually.
- Corn can cross-pollinate. If you're a first-time corn grower, plant only a single corn variety in your garden to avoid cross-pollination. Cross-pollination could mean that your ears of corn will be tough and not very sweet.
- Corn can't be hurried. Plant when it is time to plant, and harvest when it is time to harvest. Seeds won't germinate if the soil is too cool and soggy, and if weather or whim do not produce corn by July 4th, that's just the way it goes.
If you follow the "rules" of planting corn, you'll likely be rewarded with healthy corn stalks that produce one to two ears of corn per stalk. The typical backyard corn is a bit shorter than store-bought, and the ears are smaller, but the sweetness is not to be matched. You'll find it hard to go back to buying your corn at the grocery store after one successful harvest.
Good Corn Varieties For Backyard Gardens
su - Sweet corn, white
Easy to grow, dependable
se - Sugar enhanced, yellow
Northern Xtra Sweet
sh2 - bicolor
sh2 - white
Very sweet, earlier crop
se - Sugar enhanced, white
Easy to grow, dependable
Corn Grown in a Raised Bed
How to Plant Corn
Choose an area of your garden that has not previously grown a "heavy feeder" crop like tomatoes. If you have no choice about where you plant, then pay particular attention to soil preparation to ensure it has sufficient nutrition.
Your location should get full sun for most of the day, and be partially sheltered from wind if possible. You will be planting in blocks, so ideally, each block should be no smaller than 3'x3' square, and containing rows that are about a foot apart. (So a 3'x3' block will contain 3 short rows about a foot apart.) You can "cram" many corn plants into that space, so if you have only one block for planting, it will still work.
Estimating Planting Time
Corn does best when direct sown in the garden. It is possible to start them up in peat pots, but corn plants don't like having their roots disturbed on transplant, so corn starts need to be handled carefully. In either case, corn should not go into the garden until all danger of frost is past and the soil is warm, at least 50 degrees Fahrenheit for sweet corn. Super-sweet corn does best when soil is at least 60 degrees. In Southern California, I plant corn after May 1st.
About 2-4 weeks before planting time, turn the soil over and amend with manure. Begin watering the soil so that the manure has time to decompose a bit before planting. Add bagged garden soil if you like. You're aiming for soil that feels like a souffle when you mound it with your hands, something with substance but that still has lightness.
When the weather is warm and there is no frost danger, shape mounded rows of soil in the planting area. For a 3'x3' block, I make three short rows of mounded soil.
Plant corn seeds in the mounded rows that you've prepared:
- If you're planting regular sweet corn, like Silver Queen,make small holes about 1 1/2" deep and 6"-8" apart down the rows.
- If you're planting super sweet corn, like How Sweet It Is, make small holes about 1" deep and 6"-8" apart down the rows.
Drop one or two seeds in each hole. Cover with soil and press well, so that the seeds make good soil contact.
Once all rows are planted, water well.
In a week or so, you should see green seedlings. When they are about 10" tall, scatter a slow-release nitrogen based fertilizer like Miracle-Gro Shake 'n Feed Continuous Release fertilizer, or a specialty high nitrogen fertilizer for corn. You'll want the fertilizer to meet the soil around the base (or off to the sides) of the plants, not hitting the plants or inside of them.
At this point, you can also remove any "weak" looking seedlings, saving only the strongest. I typically don't thin anything because I only plant a single block of corn and want to grow as many stalks as possible in my growing season. As long as you keep up with feeding and watering, the corn doesn't seem to mind being crowded.
Feed corn about every 30 days, even if using Miracle-Gro Shake 'n Feed Continuous Release fertilizer. and be sure to water deeply and well. Without sufficient water, ears won't form. Gardeners must be diligent about watering and fertilizing!
Sometimes, corn stalks will appear to "branch" from the soil line. These are suckers that grow at the base of the cornstalk. They won't hurt anything, but if you want to remove the suckers you can. If anything, cleaning them up may keep critters from making nests in the middle of your stand of corn.
When the corn tassels, that is, when you can see the corn silks forming, pay close attention to the tops of the corn. Note how the pollen forms and how the wind distributes the pollen down to the tassels. If you've only planted a single block of corn, you may wish to ensure that the pollen is distributed evenly to each forming ear of corn. This will help the ears form with minimal missing kernels.
To distribute pollen manually, take a paper lunch bag and tap pollen into the bottom of the bag. Then put the bag over an ear of corn, closing the bottom of the bag around the base of the ear. Lightly tap or gently shake the bag to distribute pollen evenly over the tassel. Repeat the process on the remaining ears.
Raccoons, Corn Predator
Once the corn tassels, the ears develop rapidly and will generally be ready for harvesting about 21 days later. Look for signs of readiness that include:
- Firm, well-filled ears
- Dried tassels
- Ears pulling slightly away from stalk
- Kernels that burst easily when pressed with a thumbnail.
I usually sacrifice an ear of corn or two to test for readiness, pulling the corn husks completely away to get a good look at the ear.
A Last Word About Pests and Marauders
Our neighborhood has a wandering band of raccoons that routinely wreak havoc upon our gardens. They have been known to decimate stands of corn in mere hours, but I can't bring myself to do anything that might harm them. Thus, I end up "sharing" my harvest with them each year. By "sharing" I mean that some years, they get all the corn and I get none. You can take your own path where raccoons or other pests are concerned. I keep my back door locked and hope for the best.