The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Thief River Falls you can estimate when it's possible to plant lettuce by referring to 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.

You can plant lettuce a little earlier in the year because they do well in moderate cold.

The earliest that you can plant lettuce in Thief River Falls 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 lettuce and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lettuce may not have a chance to fully mature. If you are starting your lettuce indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Thief River Falls the average date of last frost happens on May 15. It might get as low as -35°F during the coldest months of winter.

Always keep in mind 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 Thief River Falls and it is different every year. Since half of the time in Thief River Falls it frosts late in the year after May 15 be ready to protect your lettuce if you have a late frost.

USDA Zone Info for Thief River Falls

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Thief River Falls

You may be interested in your other planting guides for Thief River Falls.