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.

In Riverside you can determine when it's the best time to plant lettuce by reviewing the USDA zone info.

Planting Calendar for Lettuce

Frost tolerance for lettuce:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Lettuce are one of those plants that can tolerate a little bit of cold weather which tells us that you can start planting them earlier than more sensitive plants.

The earliest that you can plant lettuce in Riverside 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 lettuce and expect a good harvest is probably September. If you wait any later than that and your lettuce may not have a chance to fully mature. You can get started a few weeks earlier by starting your lettuce indoors.

Last Frost Date

The average date of last frost is April 15 in Riverside. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Riverside may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Riverside you get a frost after April 15 so always be ready to protect your lettuce in the event of one of those late frosts.

USDA Zone Info for Riverside

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Riverside

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