One of only a few vegetables native to the Americas, sweet corn is one of the joys of a Colorado summer. What started out as colorful Indian corn has developed into the two most familiar sweet corn varieties today: yellow corn and white corn. Corn is a versatile vegetable (also considered a grain and a fruit) for home gardeners because it’s eaten fresh (on or off the cob) or cooked into many dishes. Commercially it’s ground into cornmeal and made into corn oil, cornstarch, corn syrup, and much more.
How to Grow Corn
Corn is a warm-season crop that needs heat to grow well. If you wait for the soil to warm to at least 70 degrees before planting, corn seeds will germinate quickly. There are many varieties of sweet corn to choose from, with maturity dates that range from 65 to 90 days. For a steady supply, plant early, mid-season, and late varieties. An alternate method is to plant one variety, in succession about 7-10 days apart.
- Corn needs full sun, so set aside a garden space for your corn field.
- Corn also needs rich, well-amended, and well-draining soil. Use a preplant fertilizer to broadcast over the planting area and dig in plenty of organic compost or well-aged manure.
- Keep in mind that you’ll get about 1-3 ears of corn from each corn stalk. As a rough estimate, a 10-foot row may yield about 24 ears of corn, so plan accordingly.
- Plant corn seeds (or plants) in the garden when the soil has warmed, even if it means waiting until June to plant it.
- The best planting method is to plant in short blocks of rows, which helps improve pollination. The rows should be placed 3” apart.
- Plant seeds ½” to 1” deep and 4” to 5” apart in the row.
- Once plants germinate and start to grow (about 5” to 6” tall), thin to 10” apart. If you neglect this step, the plants will become overcrowded, resulting in small, partially filled ears of corn.
- Decide on your method for watering, such as a soaker hose, and put it into place. A layer of straw mulch placed between the rows will help maintain soil moisture and keep down the weeds.
- Keep up good gardening practices and make sure soil is watered deeply and kept consistently moist; not too soggy and not too dry. You’ll want to work at growing healthy leaves on each stalk for the sweetest corn.
- Because corn plants should be “knee-high by the Fourth of July,” plan on side dressing with a nitrogen fertilizer about that same time. Sprinkle fertilizer on both sides of the rows of corn plants, 6” to 8” away from the plant. Water after raking in the fertilizer.
- Sweet corn produces a tassel of silks at the top of each stalk that grow in a tight bunch. The corn silks are pollinated by the wind. When tassels start to dry and turn brown, start checking the ears and get ready to harvest.
- Corn should be ready to harvest when the kernels are plump and juicy and the perfect color for the variety. Start checking the corn about three weeks after tassels form by pressing a fingernail into a kernel. If a milky juice oozes out, the corn is ready to harvest.
- Harvest ears by hand, breaking them from the stalk and either icing them or cooling them in ice water. This cooling helps maintain sweetness, because corn’s sugar begins to turn to starch as soon as each ear is picked.
- Leave the husks and silk on the ears and remove just before cooking or grilling.
Plant corns with these companions:
- Early potatoes
Materials for Success
- Soil thermometer
- Soaker hose
- High-quality compost or well-aged manure
- High-nitrogen fertilizer
- Organic mulch (like straw)
To learn more about growing corns or about growing your own edible vegetable garden, contact the pros at Nick’s Garden Center.