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.

One way of determining when it's possible to plant pennyroyal is to examine the USDA zone info for Ballwin.

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 other plants that might not handle the cold.

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

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Ballwin. It might get as low as -10°F during the coldest months of winter.

Keep in mind that USDA zone info for Ballwin 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 Ballwin it frosts late in the year after April 15 be ready to cover your pennyroyal in the event of a surprise late frost.

USDA Zone Info for Ballwin

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 Ballwin

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