The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to estimate when it's possible to plant pennyroyal by using the USDA zone info for Dover.

Planting Calendar for Pennyroyal

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

Pennyroyal tend to make it in pretty solid cold which means that you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant pennyroyal in Dover 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. Any later than that and your pennyroyal may not have a chance to really do well. Starting your pennyroyal indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Dover. You should expect an average low temperature of -10°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Dover and it can change quite a bit from year to year. Half of the time in Dover it frosts late in the year after April 15 so make sure that you are prepared to protect your pennyroyal in the event of a surprise late frost.

USDA Zone Info for Dover

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 Dover

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