One of the best tools that you have as gardeners to help us estimate 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.

You will be able to determine when it's a good idea to plant romaine lettuce by looking at the USDA zone info for Willmar.

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 tend to make it in cold weather which tells us that you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant romaine lettuce in Willmar is March. However, you really should wait until April 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 August. Any later than that and your romaine lettuce may not have a chance to grow to maturity. Starting your romaine lettuce indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Willmar. In the coldest months of winter you should expect an average low temperature of -25°F.

Always keep in mind that USDA zone info for Willmar is not always accurate and the actual date of last frost is different every year. Since half of the time in Willmar you get a frost after May 15 be ready to cover your romaine lettuce if you have a late frost.

USDA Zone Info for Willmar

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Willmar

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