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

In Havre you can estimate when it's the best time to plant black eyed susans by looking at the USDA zone info.

Planting Calendar for Black Eyed Susans

Frost tolerance for black eyed susans:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since black eyed susans require warm weather you have to wait until after the last frost before you can plant them.

The earliest that you can plant black eyed susans in Havre 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 black eyed susans and expect a good harvest is probably August. If you wait any later than that and your black eyed susans may not have a chance to fully mature. If you are starting your black eyed susans indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Havre. You should expect an average low temperature of -30°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Havre and it is different every year. Half of the time in Havre last frost occurs after May 15 so always be ready to protect your black eyed susans in the event of a surprise late frost.

USDA Zone Info for Havre

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 Havre

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