One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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 estimating when it's possible to plant coreopsis is to look at the USDA zone info for Sterling.

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 moderately cold tolerant you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant coreopsis in Sterling is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant coreopsis and expect a good harvest is probably September. Any later than that and your coreopsis may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your coreopsis indoors.

Last Frost Date

In Sterling the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Sterling is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Sterling it frosts late in the year after April 15 so just be sure to be ready to cover your coreopsis in the event of a surprise late frost.

USDA Zone Info for Sterling

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Sterling

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