One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

You can figure out when it's a good idea to plant pennyroyal in Dearborn by using 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.

Pennyroyal can survive in pretty solid cold which tells us that you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant pennyroyal in Dearborn 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 pennyroyal and expect a good harvest is probably September. If you wait any later than that and your pennyroyal may not have a chance to grow to maturity. If you are starting your pennyroyal indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Dearborn. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Dearborn is not always accurate the actual date of last frost is different every year. Half of the time in Dearborn there is a last frost after April 15 so just be sure to be ready to protect your pennyroyal in the event of a late frost.

USDA Zone Info for Dearborn

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°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 0°F.

Plants to Grow in Dearborn

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