One of the best tools that you have as gardeners to help us determine 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 first chance to plant pennyroyal in Zone 6b can be determined 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 Zone 6b 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 really do well. If you are starting your pennyroyal indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Zone 6b. It might get as low as -5°F during the coldest months of winter.

It's important to remember that USDA zone info for Zone 6b may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Zone 6b 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 Zone 6b

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 Zone 6b

You may be interested in your other planting guides for Zone 6b.