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 Portsmouth you can determine when it's the best time to plant corn by looking at the USDA zone info.

Planting Calendar for Corn

Frost tolerance for corn:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since corn are not cold tolerant you need to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant corn in Portsmouth 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 corn and expect a good harvest is probably August. Any later than that and your corn may not have a chance to really do well. Starting your corn indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Portsmouth the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Always keep in mind that USDA zone info for Portsmouth is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Portsmouth last frost occurs after April 15 be ready to protect your corn in the event of one of those late frosts.

USDA Zone Info for Portsmouth

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Portsmouth

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