One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to estimate when it's possible to plant sweet corn by checking out the USDA zone info for Great Falls.

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 tells us that you can start planting them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant sweet corn in Great Falls 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. If you wait 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 couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Great Falls. It might get as low as -30°F during the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Great Falls and it will vary from year to year. Since half of the time in Great Falls last frost occurs after May 15 be ready to cover your sweet corn in the event of a late frost.

USDA Zone Info for Great Falls

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 Great Falls

You may be interested in your other planting guides for Great Falls.