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.

You can figure out when it's the best time to plant romaine lettuce in San Marcos by using 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 much earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant romaine lettuce in San Marcos 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 fully mature. 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 March 15 in San Marcos. In the coldest months of winter you can expect an average low temperature of 15°F.

Always keep in mind that USDA zone info for San Marcos is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in San Marcos there is a last frost after March 15 so always be ready to cover your romaine lettuce in the event of a surprise late frost.

USDA Zone Info for San Marcos

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in San Marcos

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