The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of making a decision about when to plant calibrachoa is to look at the USDA zone info for River Falls.

Planting Calendar for Calibrachoa

Frost tolerance for calibrachoa:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Calibrachoa can survive in a tiny bit of cold which tells us that you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant calibrachoa in River Falls 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 calibrachoa and expect a good harvest is probably August. Any later than that and your calibrachoa may not have a chance to grow to maturity. Starting your calibrachoa indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is 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 may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in River Falls you get a frost after May 15 so just be sure to be ready to cover your calibrachoa if you have 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.