Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. 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 the best time to plant romaine lettuce by referring to the USDA zone info for Plymouth.

Planting Calendar for Romaine lettuce

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

Romaine lettuce do ok in pretty solid cold which tells us that you can plant them a lot earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant romaine lettuce in Plymouth 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. Any later than that and your romaine lettuce may not have a chance to really do well. You can get started a little bit earlier by starting your romaine lettuce indoors.

Last Frost Date

The average date of last frost is April 15 in Plymouth. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Plymouth is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Plymouth last frost occurs after April 15 so be sure to be ready to cover your romaine lettuce if you have a surprise late frost.

USDA Zone Info for Plymouth

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 Plymouth

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