When to Plant Sweet corn in Harlan, IA

Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to determine when to plant sweet corn by looking at the USDA zone info for Harlan.


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 do ok in moderate cold which means that you can get them planted just a bit earlier than more sensitive 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 Harlan 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. You probably don't want to wait any later than that or else your sweet corn may not have a chance to really do well. Starting your sweet corn indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Harlan. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Harlan is an average the actual date of last frost changes from year to year. Half of the time in Harlan last frost occurs after April 15 so make sure that you are ready to cover your sweet corn in the event of a late frost.

USDA Zone Info for Harlan

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-20°F
Highest Expected Low-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Harlan

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