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

In Thief River Falls you can figure out when to plant tropical water plants by using the USDA zone info.

Planting Calendar for Tropical Water Plants

Frost tolerance for tropical water plants:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since tropical water plants require warm weather it's important to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant tropical water plants 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 tropical water plants and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tropical water plants may not have a chance to really do well. If you are starting your tropical water plants indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Thief River Falls the average date of last frost happens on May 15. You can expect an average low temperature of -35°F in the coldest months of winter.

Since the USDA zone info for Thief River Falls is an average the actual date of last frost will vary from year to year. Half of the time in Thief River Falls there is a last frost after May 15 so always be ready to cover your tropical water plants 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.