One of the best tools that you have as gardeners to help us determine 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.

The first chance to plant spearmint in Decorah can be estimated by checking out the USDA zone info.

Planting Calendar for Spearmint

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

Spearmint tend to make it in pretty solid cold which means that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant spearmint in Decorah 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 fully mature. You can get started a few weeks earlier by starting your spearmint indoors.

Last Frost Date

The average date of last frost is May 15 in Decorah. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Decorah is an average the actual date of last frost will vary from year to year. Half of the time in Decorah you get a frost after May 15 so make sure that you are prepared to protect your spearmint if you have a surprise late frost.

USDA Zone Info for Decorah

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 Decorah

You may be interested in your other planting guides for Decorah.