Before planting it is a good idea to find your USDA Zone info to determine 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 figure out when it's the best time to plant romaine lettuce by reviewing the USDA zone info for Seattle.

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 are one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them much earlier than more sensitive plants.

The earliest that you can plant romaine lettuce in Seattle 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. If you wait any later than that and your romaine lettuce may not have a chance to fully mature. You can get started a few weeks earlier by starting your romaine lettuce indoors.

Last Frost Date

In Seattle the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 15°F.

Keep in mind that USDA zone info for Seattle is an average and the actual date of last frost changes from year to year. Since half of the time in Seattle you get surprised by a frost after March 15 be ready to cover your romaine lettuce in the event of a late frost.

USDA Zone Info for Seattle

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Seattle

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