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

The USDA zone info for Portland should be read to determine when it's the best time to plant romaine lettuce.

Planting Calendar for Romaine lettuce

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

Since romaine lettuce do well in cold you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant romaine lettuce in Portland 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 fully mature. You can get started a little bit earlier by starting your romaine lettuce indoors.

Last Frost Date

In Portland the average date of last frost happens on April 15. You can expect an average low temperature of 0°F in the coldest months of winter.

Remember that USDA zone info for Portland is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Portland last frost occurs after April 15 be ready to cover your romaine lettuce in the event of one of those late frosts.

USDA Zone Info for Portland

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Portland

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