One of the first steps you take when you are getting a good idea 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.

In Vernal you can figure out when it's a good idea to plant pennyroyal 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.

Pennyroyal do well in cold which tells us that you can plant them a quite a bit earlier than plants that are more sensitive to the cold.

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

Last Frost Date

On average the last frost has passed is on April 15 in Vernal. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Vernal is not always accurate the actual date of last frost is different every year. Half of the time in Vernal there is a last frost after April 15 so be sure to be ready to cover your pennyroyal in the event of one of those late frosts.

USDA Zone Info for Vernal

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Vernal

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