One of the best tools that you have as gardeners to help us estimate 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.

A way of figuring out when you can plant sweet corn is to consult the USDA zone info for South Portland.

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 mild cold which means that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant sweet corn in South Portland 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 fully mature. Starting your sweet corn indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in South Portland. You can expect an average low temperature of -15°F in the coldest months of winter.

It's important to remember that USDA zone info for South Portland is an average and the actual date of last frost changes from year to year. Half of the time in South Portland there is a last frost after April 15 so be sure to be ready to protect your sweet corn in the event of a late frost.

USDA Zone Info for South Portland

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in South Portland

You may be interested in your other planting guides for South Portland.