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 USDA zone info for Thief River Falls can be reviewed to estimate when it's a good idea to plant oxalis.

Planting Calendar for Oxalis

Frost tolerance for oxalis:	Not tolerant of frost.
When to plant:	After the last frost.

It's a bad idea to plant oxalis until after the last frost has passed because they are not cold tolerant.

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

Last Frost Date

On average the last frost 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 USDA zone info for Thief River Falls may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Thief River Falls there is a last frost after May 15 so be sure to be ready to protect your oxalis 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.