The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Watertown you can determine when you can plant sweet corn 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.

Since sweet corn are barely cold tolerant you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant sweet corn in Watertown 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 really do well. 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 May 15 in Watertown. It might get as low as -30°F during the coldest months of winter.

Always keep in mind that USDA zone info for Watertown is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Watertown last frost occurs after May 15 so just be sure to be ready to protect your sweet corn if you have a surprise late frost.

USDA Zone Info for Watertown

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 Watertown

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