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.

The first opportunity to plant pennyroyal in Hibbing can be figured out by reviewing the USDA zone info.

Planting Calendar for Pennyroyal

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

Since pennyroyal do well in cold you can plant them quite a bit earlier in the year than other frost tender plants.

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

Last Frost Date

In Hibbing the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -35°F.

Since the USDA zone info for Hibbing is just an average the actual date of last frost changes from year to year. Half of the time in Hibbing last frost occurs after May 15 so always be ready to cover your pennyroyal in the event of a surprise late frost.

USDA Zone Info for Hibbing

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Hibbing

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