When to plant lettuce in zone 9b

The zone 9b schedule for lettuce

Start seeds indoors

December 6 to 20

Plant out

January 24 to February 7

Sow outdoors

January 10 to 17

First harvest, roughly

February 23 to April 18

Plant for a fall crop

September 9 to October 14

From the median frost dates of the NOAA stations assigned to the 1,459 ZIP codes in zone 9b, and the timing recommended by Cooperative Extension guides for lettuce.

Dates before the last frost assume the soil has thawed and is dry enough to work: a squeezed handful crumbles instead of sticking. After a late or wet spring, wait for that even if the date has passed.

Frost risk in zone 9b

Zones are based on winter cold, not on frost dates, so the last spring frost varies a lot within a zone. Across zone 9b, the typical last frost ranges from about January 12 in the earliest tenth of ZIP codes to March 1 in the latest tenth, and the first fall frost from January 8 to December 28. For a typical place in the zone:

• December 18Risky: a later frost happens in 9 years out of 10
• January 31Typical: frost after this date in half of years
• March 1Safe: a later frost only 1 year in 10

Lettuce in zone 9b cities