Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. 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 Corona can be used to determine 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.

You can plant romaine lettuce quite a bit earlier in the year because they do well in cold.

The earliest that you can plant romaine lettuce in Corona 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. If you wait any later than that and your romaine lettuce may not have a chance to really do well. Starting your romaine lettuce indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Corona. You should expect an average low temperature of 25°F in the coldest months of winter.

It's important to remember that USDA zone info for Corona is an average and the actual date of last frost will vary from year to year. Half of the time in Corona you get a frost after February 15 so make sure that you are prepared to cover your romaine lettuce if you have a late frost.

USDA Zone Info for Corona

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 Corona

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