One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant bishop's weed in Thief River Falls can be figured out by using the USDA zone info.

Planting Calendar for Bishop's Weed

Frost tolerance for bishop's weed:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since bishop's weed do well in cold you can plant them quite a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant bishop's weed 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 bishop's weed and expect a good harvest is probably August. Any later than that and your bishop's weed may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your bishop's weed indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Thief River Falls. It might get as low as -35°F during the coldest months of winter.

Remember that USDA zone info for Thief River Falls is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Thief River Falls you get surprised by a frost after May 15 be ready to cover your bishop's weed in the event of a surprise 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.