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

By looking at the USDA zone info for Flint it's a good idea to figure out when it's the best time to plant pennyroyal.

Planting Calendar for Pennyroyal

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

Pennyroyal are very cold tolerant which tells us that you can plant them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant pennyroyal in Flint 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. You probably don't want to wait any later than that or else your pennyroyal may not have a chance to fully mature. 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 Flint. In the coldest months of winter you should expect an average low temperature of -10°F.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Flint and it will vary from year to year. Since half of the time in Flint there is a last frost after April 15 be ready to cover your pennyroyal in the event of one of those late frosts.

USDA Zone Info for Flint

Here is the info for USDA Zone 6a.

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

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

Plants to Grow in Flint

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