Planting According to Weather
One of the most important things when it comes to planting sweet corn is warmth. Corn seeds need heat to germinate, so if you plant corn too early, it will take as long as three weeks to germinate. Or, if it is too cold, it might not germinate at all.
- A good rule of thumb is to plan on sowing your corn seeds when the air temperature is consistently 70°F (21°C) for about two weeks.
- In most areas, two weeks after the last frost of the season is the ideal time to plant sweet corn.
Tip: If you live somewhere that often has late frosts, you can cover your rows with plastic sheeting to retain the heat.
Planting According to Soil Temperature
If you are not experienced with gauging when to plant your corn by the air temperature, you can also measure the soil temperature. The ideal soil temperature for planting sweet corn seeds is 55°F minimum (13°C).
Most home and garden stores carry soil thermometers, which allow you to probe the ground at the depth you want to plant and it will measure the temperature. This is an inexpensive way to take the guesswork out of it.
If you want to have sweet corn all summer long as well as corn to preserve, you can stagger your planting. When you stagger plant, you sow a few rows of seed and then plant every two weeks again. Depending on the variety of sweet corn you plant and where you live, you can often plant corn at the end of July and still be able to harvest it before the frost comes.
Tip: If you are planting more than one variety of corn, do not plant the seeds within 100 feet of each other. You run the risk of cross-pollination which can result in a bitter harvest!
When it comes to planting sweet corn, you have many varieties to choose from and can easily plant through most of the summer. Once the weather is consistently warm, you do not have to wait to plant. As long as you water and fertilize your corn plants, you are almost guaranteed as much sweet corn as you can eat!