One of the best tools that you have as gardeners to help us determine 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 should be reffered to in order to determine when it's the best time to plant spearmint.

Planting Calendar for Spearmint

Frost tolerance for spearmint:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant spearmint a lot earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant spearmint in River Falls is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant spearmint and expect a good harvest is probably August. If you wait any later than that and your spearmint may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your spearmint indoors.

Last Frost Date

On average the last frost is on May 15 in River Falls. In the coldest months of winter you should expect an average low temperature of -25°F.

Just be sure to remember that USDA zone info for River Falls is just an average and the actual date of last frost is different every 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 spearmint 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.