One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's the best time to plant romaine lettuce in Portsmouth by referring to the USDA zone info.

Planting Calendar for Romaine lettuce

Frost tolerance for romaine lettuce:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant romaine lettuce earlier in the year because they are very cold tolerant.

The earliest that you can plant romaine lettuce in Portsmouth is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant romaine lettuce and expect a good harvest is probably September. You probably don't want to wait any later than that or else your romaine lettuce may not have a chance to grow to maturity. Starting your romaine lettuce indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Portsmouth. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Portsmouth is not always accurate the actual date of last frost is different every year. Since half of the time in Portsmouth last frost occurs after April 15 be ready to protect your romaine lettuce in the event of a late frost.

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.