The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 Willoughby you should be able to determine when you can plant pennyroyal.

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 earlier in the year than more sensitive plants.

The earliest that you can plant pennyroyal in Willoughby 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 grow to maturity. You can get started a couple of weeks earlier by starting your pennyroyal indoors.

Last Frost Date

In Willoughby the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Willoughby is not always accurate the actual date of last frost is different every year. Half of the time in Willoughby it frosts late in the year after April 15 so make sure that you are prepared to cover your pennyroyal if you have a late frost.

USDA Zone Info for Willoughby

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 Willoughby

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