One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of figuring out when you can plant pennyroyal is to use the USDA zone info for Donna.

Planting Calendar for Pennyroyal

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

Pennyroyal are one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them a quite a bit earlier than other frost tender plants.

The earliest that you can plant pennyroyal in Donna is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant pennyroyal and expect a good harvest is probably October. You probably don't want to wait any later than that or else your pennyroyal may not have a chance to really do well. You can get started a little bit earlier by starting your pennyroyal indoors.

Last Frost Date

On average the last frost is on February 15 in Donna. In the coldest months of winter you should expect an average low temperature of 25°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Donna and it changes from year to year. Since half of the time in Donna it frosts late in the year after February 15 be ready to cover your pennyroyal in the event of one of those late frosts.

USDA Zone Info for Donna

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

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

Plants to Grow in Donna

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