One of the best tools that you have as gardeners to help us estimate 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.

By referring to the USDA zone info for Duluth you should be able to figure out when you can plant cuphea.

Planting Calendar for Cuphea

Frost tolerance for cuphea:	Not tolerant of frost.
When to plant:	After the last frost.

Since cuphea require warm weather it is important to wait until after the last frost before you can plant them.

The earliest that you can plant cuphea in Duluth is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant cuphea and expect a good harvest is probably August. Any later than that and your cuphea may not have a chance to grow to maturity. Starting your cuphea indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Duluth the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Duluth is an average the actual date of last frost will vary from year to year. Half of the time in Duluth it frosts late in the year after May 15 so be sure to be ready to protect your cuphea if you have one of those late frosts.

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.