One of the first steps you take when you are determining 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 common way of determining when you can plant dahlias is to check out the USDA zone info for Mandan.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Dahlias are not cold tolerant which means that you need to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant dahlias in Mandan 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 dahlias and expect a good harvest is probably August. You probably don't want to wait any later than that or else your dahlias may not have a chance to fully mature. If you are starting your dahlias indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Mandan. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Mandan is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Mandan you get surprised by a frost after May 15 be ready to protect your dahlias if you have a late frost.

USDA Zone Info for Mandan

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 Mandan

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