The USDA Zone info is a great tool for gardeners to help us figure out 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.

It's possible to figure out when it's possible to plant sweet williams by using the USDA zone info for Bismarck.

Planting Calendar for Sweet Williams

Frost tolerance for sweet williams:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Sweet Williams are one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them earlier than other plants that might not handle the cold.

The earliest that you can plant sweet williams in Bismarck 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 sweet williams and expect a good harvest is probably August. If you wait any later than that and your sweet williams may not have a chance to grow to maturity. Starting your sweet williams indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Bismarck. In the coldest months of winter you should expect an average low temperature of -30°F.

Since the USDA zone info for Bismarck may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Bismarck you get surprised by a frost after May 15 so just be sure to be ready to cover your sweet williams if you have one of those late frosts.

USDA Zone Info for Bismarck

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Bismarck

You may be interested in your other planting guides for Bismarck.