The USDA Zone info is a great tool for gardeners to help us estimate 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.

A way of figuring out when it's a good idea to plant sweet corn is to look at the USDA zone info for Merrill.

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 are barely cold tolerant which tells us that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant sweet corn in Merrill is April. However, you really should wait until May 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 grow to maturity. If you are starting your sweet corn indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Merrill. You should expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Merrill may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Merrill you get a frost after May 15 so be sure to be ready to protect your sweet corn if you have a surprise late frost.

USDA Zone Info for Merrill

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Merrill

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