One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. 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 it's a good idea to plant portulaca by checking out the USDA zone info.

Planting Calendar for Portulaca

Frost tolerance for portulaca:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Portulaca require warm weather which means that you have to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant portulaca 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 portulaca and expect a good harvest is probably August. Any later than that and your portulaca may not have a chance to grow to maturity. If you are starting your portulaca indoors then you might be able to get away with starting them a little bit 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 is just an average the actual date of last frost changes from year to year. Since half of the time in Thief River Falls it frosts late in the year after May 15 be ready to protect your portulaca 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.