One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of estimating when it's the best time to plant pennyroyal is to look at the USDA zone info for Harlingen.

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 a lot earlier in the year than other plants that might not handle the cold.

The earliest that you can plant pennyroyal in Harlingen 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. Any later than that and 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 little bit earlier.

Last Frost Date

On average the last frost is on February 15 in Harlingen. It might get as low as 25°F during the coldest months of winter.

Remember that USDA zone info for Harlingen may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Harlingen there is a last frost after February 15 so make sure that you are prepared to cover your pennyroyal in the event of a late frost.

USDA Zone Info for Harlingen

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 Harlingen

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