Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of determining when you can plant pennyroyal is to look at the USDA zone info for Fergus Falls.

Planting Calendar for Pennyroyal

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

Pennyroyal are very cold tolerant which tells us that you can get them planted much earlier than other frost tender plants.

The earliest that you can plant pennyroyal in Fergus Falls is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant pennyroyal and expect a good harvest is probably August. You probably don't want to wait any later than that or else your pennyroyal may not have a chance to fully mature. If you are starting your pennyroyal indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Fergus Falls the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -30°F.

It's important to remember that USDA zone info for Fergus Falls may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Fergus Falls last frost occurs after May 15 be ready to cover your pennyroyal if you have a late frost.

USDA Zone Info for Fergus Falls

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Fergus Falls

You may be interested in your other planting guides for Fergus Falls.