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.

By using the USDA zone info for Zone 4a it's possible to figure out when to plant coreopsis.

Planting Calendar for Coreopsis

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

Since coreopsis are one of those plants that can tolerate a little bit of cold weather you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant coreopsis in Zone 4a 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 coreopsis and expect a good harvest is probably August. If you wait any later than that and your coreopsis may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your coreopsis indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 4a. You should expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Zone 4a may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Zone 4a it frosts late in the year after May 15 so be sure to be ready to cover your coreopsis in the event of a 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.