One of the first steps you take when you are making a decision about 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.

A way of determining when it's possible to plant coreopsis is to refer to the USDA zone info for Zone 4b.

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 little bit earlier in the year than other frost tender plants.

The earliest that you can plant coreopsis in Zone 4b 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. You probably don't want to wait any later than that or else your coreopsis may not have a chance to really do well. Starting your coreopsis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Zone 4b the average date of last frost happens on May 15. You can expect an average low temperature of -25°F in the coldest months of winter.

Keep in mind that USDA zone info for Zone 4b is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Zone 4b last frost occurs 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 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

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