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

It's possible to estimate when you can plant spearmint by reviewing the USDA zone info for Iowa City.

Planting Calendar for Spearmint

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

Spearmint do well in pretty solid cold which tells us that you can plant them much earlier in the year than plants that are more sensitive to the cold.

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

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

Last Frost Date

The average date of last frost is April 15 in Iowa City. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Iowa City is not always accurate the actual date of last frost will vary from year to year. Half of the time in Iowa City last frost occurs after April 15 so always be ready to cover your spearmint in the event of a surprise late frost.

USDA Zone Info for Iowa City

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Iowa City

You may be interested in your other planting guides for Iowa City.