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.

One way of getting a good idea when it's a good idea to plant alyssum is to check out the USDA zone info for Thief River Falls.

Planting Calendar for Alyssum

Frost tolerance for alyssum:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Alyssum are very cold tolerant which tells us that you can plant them much earlier than more sensitive plants.

The earliest that you can plant alyssum 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 alyssum and expect a good harvest is probably August. If you wait any later than that and your alyssum may not have a chance to really do well. You can get started a little bit earlier by starting your alyssum indoors.

Last Frost Date

The average date of last frost is May 15 in Thief River Falls. In the coldest months of winter you should expect an average low temperature of -35°F.

Always keep in mind 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 is different every year. Half of the time in Thief River Falls it frosts late in the year after May 15 so be sure to be ready to cover your alyssum in the event of 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.