The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant alternaria in Thief River Falls should be figured out by using the USDA zone info.

Planting Calendar for Alternaria

Frost tolerance for alternaria:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Alternaria require warm weather which tells us that it's necessary to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant alternaria 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 alternaria and expect a good harvest is probably August. If you wait any later than that and your alternaria may not have a chance to fully mature. Starting your alternaria indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Thief River Falls may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Thief River Falls last frost occurs after May 15 be ready to cover your alternaria 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.