Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant black eyed susans in Zone 4a should be estimated by reviewing the USDA zone info.

Planting Calendar for Black Eyed Susans

Frost tolerance for black eyed susans:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's not a good idea to plant black eyed susans until after the last frost because they do not do well in cold weather.

The earliest that you can plant black eyed susans in Zone 4a 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. You probably don't want to wait any later than that or else your black eyed susans may not have a chance to grow to maturity. Starting your black eyed susans indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Zone 4a. In the coldest months of winter you can expect an average low temperature of -30°F.

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 Zone 4a and it will vary from year to year. Since half of the time in Zone 4a last frost occurs after May 15 be ready to protect your black eyed susans if you have a surprise late frost.

USDA Zone Info for Zone 4a

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 Zone 4a

You may be interested in your other planting guides for Zone 4a.