One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant romaine lettuce in California can be figured out by looking at 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.

Since romaine lettuce are one of those plants that can tolerate quite a bit of cold weather you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant romaine lettuce in California 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. Any later than that and your romaine lettuce may not have a chance to really do well. If you are starting your romaine lettuce indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in California. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for California is an average the actual date of last frost will vary from year to year. Half of the time in California you get surprised by a frost after April 15 so always be ready to cover your romaine lettuce if you have a surprise late frost.

USDA Zone Info for California

Here is the info for USDA Zone 6b.

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

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

Plants to Grow in California

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