One of the first steps you take when you are getting a good idea 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.

The USDA zone info for River Falls can be looked at to estimate when it's the best time to plant lisianthus.

Planting Calendar for Lisianthus

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

Since lisianthus do not do well in cold weather you need to wait until after the last frost has passed before you can plant them.

The earliest that you can plant lisianthus 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 lisianthus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lisianthus may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your lisianthus indoors.

Last Frost Date

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

Since the USDA zone info for River Falls is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in River Falls you get surprised by a frost after May 15 so just be sure to be ready to cover your lisianthus in the event of a surprise 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.