One of the first steps you take when you are estimating your gardening schedule is find your 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 figure out when it's a good idea to plant tarragon by looking at the USDA zone info for Thief River Falls.

Planting Calendar for Tarragon

Frost tolerance for tarragon:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since tarragon are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than other frost tender plants.

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

The last month that you can plant tarragon and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tarragon may not have a chance to really do well. You can get started a few weeks earlier by starting your tarragon indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Thief River Falls. 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 changes from year to year. Half of the time in Thief River Falls you get surprised by a frost after May 15 so be sure to be ready to protect your tarragon if you have 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.