One of the first steps you take when you are determining 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.

By using the USDA zone info for Thief River Falls you should be able to determine when it's the best time to plant sweet sultan.

Planting Calendar for Sweet Sultan

Frost tolerance for sweet sultan:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Sweet Sultan tend to make it in very little cold which tells us that you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant sweet sultan in Thief River Falls is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant sweet sultan and expect a good harvest is probably August. Any later than that and your sweet sultan may not have a chance to really do well. You can get started a little bit earlier by starting your sweet sultan indoors.

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.

Just be sure to remember 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 will vary 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 sweet sultan 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.