One of the first steps you take when you are making a decision about your gardening schedule is find your 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 USDA zone info for Rio Grande City should be used to figure out when it's possible 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 do ok in a bit of cold which means that you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant romaine lettuce in Rio Grande City 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 fully mature. If you are starting your romaine lettuce indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in Rio Grande City. You should expect an average low temperature of 25°F in the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Rio Grande City and it can change quite a bit from year to year. Since half of the time in Rio Grande City you get a frost after February 15 be ready to cover your romaine lettuce in the event of a surprise late frost.

USDA Zone Info for Rio Grande City

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 Rio Grande City

You may be interested in your other planting guides for Rio Grande City.