One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Duluth should be looked at to estimate when it's the best time 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.

You can plant coreopsis a little bit earlier in the year because they do well in moderate cold.

The earliest that you can plant coreopsis in Duluth 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 few weeks earlier.

Last Frost Date

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

It's important to remember that USDA zone info for Duluth is an average and the actual date of last frost will vary from year to year. Half of the time in Duluth there is a last frost after May 15 so just be sure to be ready to protect your coreopsis in the event of a surprise late frost.

USDA Zone Info for Duluth

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 Duluth

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