When to Plant Sweet corn in Alton, IL

The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant sweet corn in Alton should be estimated by reviewing the USDA zone info.


Planting Calendar for Sweet corn

Frost tolerance for sweet corn: Tolerant of a very small amount of frost.
When to plant: Up to 3 weeks before last frost.

Sweet corn can survive in very little cold which tells us that you can plant them slightly earlier in the year than other frost tender plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant sweet corn
Possibly ok, but a risky time to plant sweet corn
Probably not a good time to plant sweet corn

The earliest that you can plant sweet corn in Alton is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant sweet corn and expect a good harvest is probably August. Any later than that and your sweet corn may not have a chance to really do well. You can get started a couple of weeks earlier by starting your sweet corn indoors.

Last Frost Date

In Alton the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Alton and it will vary from year to year. Since half of the time in Alton you get a frost after April 15 be ready to protect your sweet corn if you have a late frost.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-10°F
Highest Expected Low-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Alton

You may be interested in your other planting guides for Alton.