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When to Plant Romaine lettuce in Riverside, CA

One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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 first chance to plant romaine lettuce in Riverside can be estimated 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 very cold tolerant you can plant them much earlier in the year than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant romaine lettuce
Possibly ok, but a risky time to plant romaine lettuce
Probably not a good time to plant romaine lettuce

The earliest that you can plant romaine lettuce in Riverside 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 grow to maturity. If you are starting your romaine lettuce indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Riverside. It might get as low as 25°F during the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Riverside and it can change quite a bit from year to year. Since half of the time in Riverside you get a frost after February 15 be ready to protect your romaine lettuce in the event of a surprise late frost.

USDA Zone Info for Riverside

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 Low25°F
Highest Expected Low30°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 Riverside

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