Before planting it is a good idea to find your USDA Zone info to estimate 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.

It's possible to determine when to plant lettuce by using the USDA zone info for San Francisco.

Planting Calendar for Lettuce

Frost tolerance for lettuce:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since lettuce do well in moderate cold you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant 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 lettuce and expect a good harvest is probably October. Any later than that and your lettuce may not have a chance to fully mature. You can get started a little bit earlier by starting your lettuce indoors.

Last Frost Date

The average date of last frost is January 31 in San Francisco. You should expect an average low temperature of 35°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for San Francisco and it is different every year. Since half of the time in San Francisco you get surprised by a frost after January 31 be ready to protect your lettuce if you have a surprise late frost.

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.