One of the best tools that you have as gardeners to help us estimate 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 Duluth should be looked at 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 very cold tolerant.

The earliest that you can plant spearmint in Duluth 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. If you are starting your spearmint indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Duluth. In the coldest months of winter you should expect an average low temperature of 5°F.

Since the USDA zone info for Duluth is not always accurate the actual date of last frost is different every year. Since half of the time in Duluth you get a frost after April 15 be ready to cover your spearmint if you have one of those late frosts.

USDA Zone Info for Duluth

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Duluth

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