One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for San Ramon should be looked at to estimate when it's the best time to plant romaine lettuce.

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 can survive in pretty solid cold which means that you can plant them quite a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant romaine lettuce in San Ramon 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. Any later than that and your romaine lettuce may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your romaine lettuce indoors.

Last Frost Date

On average all chance of frost has passed is on February 15 in San Ramon. You can expect an average low temperature of 25°F in the coldest months of winter.

It's important to remember that USDA zone info for San Ramon is just an average and the actual date of last frost is different every year. Since half of the time in San Ramon you get surprised by a frost after February 15 be ready to protect your romaine lettuce if you have one of those late frosts.

USDA Zone Info for San Ramon

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in San Ramon

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