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When to Plant Romaine lettuce in Prosser, WA

Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to figure out when to plant romaine lettuce by reviewing the USDA zone info for Prosser.


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 are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them much earlier than other frost tender plants.

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 Prosser 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. You probably don't want to wait any later than that or else 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 couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Prosser. You can expect an average low temperature of 0°F in the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Prosser and it can change quite a bit from year to year. Half of the time in Prosser last frost occurs after April 15 so be sure to be ready to protect your romaine lettuce in the event of one of those late frosts.

USDA Zone Info for Prosser

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low0°F
Highest Expected Low5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Prosser

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