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.

A way of making a decision about when it's a good idea to plant asparagus fern is to look at the USDA zone info for Thief River Falls.

Planting Calendar for Asparagus Fern

Frost tolerance for asparagus fern:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since asparagus fern require warm weather it's important to wait until after the last frost before you can plant them.

The earliest that you can plant asparagus fern in Thief River Falls is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant asparagus fern and expect a good harvest is probably August. If you wait any later than that and your asparagus fern may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your asparagus fern indoors.

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.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Thief River Falls and it changes from year to year. Since half of the time in Thief River Falls you get a frost after May 15 be ready to protect your asparagus fern in the event of one of those late frosts.

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.