One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for River Falls can be reviewed to figure out when it's the best time to plant dahlias.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You should not plant dahlias until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant dahlias in River Falls 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. If you wait any later than that and your dahlias may not have a chance to really do well. Starting your dahlias indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on May 15 in River Falls. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for River Falls is not always accurate the actual date of last frost changes from year to year. Since half of the time in River Falls last frost occurs after May 15 be ready to cover your dahlias in the event of a late frost.

USDA Zone Info for River Falls

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 River Falls

You may be interested in your other planting guides for River Falls.