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.

It's a good idea to determine when it's a good idea to plant dahlias by referring to the USDA zone info for Rapid City.

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 tells us that it is important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant dahlias in Rapid City is April. However, you really should wait until May 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. Any later than that and your dahlias may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your dahlias indoors.

Last Frost Date

The average date of last frost is April 15 in Rapid City. In the coldest months of winter you can expect an average low temperature of -20°F.

Since the USDA zone info for Rapid City is just an average the actual date of last frost is different every year. Since half of the time in Rapid City you get a frost after April 15 be ready to cover your dahlias if you have a late frost.

USDA Zone Info for Rapid City

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Rapid City

You may be interested in your other planting guides for Rapid City.