One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant pennyroyal in Portsmouth should be figured out by referring to 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 are very cold tolerant you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant pennyroyal in Portsmouth 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. Starting your pennyroyal indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Portsmouth. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Portsmouth is just an average the actual date of last frost is different every year. Since half of the time in Portsmouth you get a frost after April 15 be ready to protect your pennyroyal if you have one of those late frosts.

USDA Zone Info for Portsmouth

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 Portsmouth

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