One of the first steps you take when you are getting a good idea your gardening schedule is find your 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 to plant romaine lettuce in San Francisco 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.

Romaine lettuce are very cold tolerant which means that you can get them planted much earlier than other plants that might not handle the cold.

The earliest that you can plant romaine lettuce in San Francisco is January. However, you really should wait until February 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 October. You probably don't want to wait any later than that or else your romaine lettuce may not have a chance to fully mature. Starting your romaine lettuce indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on January 31 in San Francisco. In the coldest months of winter you should expect an average low temperature of 35°F.

Always keep in mind that USDA zone info for San Francisco may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in San Francisco you get a frost after January 31 be ready to cover your romaine lettuce if you have one of those late frosts.

USDA Zone Info for San Francisco

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in San Francisco

You may be interested in your other planting guides for San Francisco.