One of the first steps you take when you are estimating 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.

You should be able to estimate when you can plant coreopsis by using the USDA zone info for Decorah.

Planting Calendar for Coreopsis

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

Coreopsis are moderately cold tolerant which tells us that you can start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant coreopsis in Decorah 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. Any later than that and your coreopsis may not have a chance to fully mature. If you are starting your coreopsis indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Decorah the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Decorah is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Decorah last frost occurs after May 15 be ready to cover your coreopsis if you have a late frost.

USDA Zone Info for Decorah

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 Decorah

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