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.

The earliest that you can plant pennyroyal in National City can be figured out by reviewing 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 means 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 National City 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 grow to maturity. You can get started a few weeks earlier by starting your pennyroyal indoors.

Last Frost Date

In National City the average date of last frost happens on January 31. It might get as low as 35°F during the coldest months of winter.

Keep in mind that USDA zone info for National City is an average and the actual date of last frost is different every year. Since half of the time in National City you get a frost after January 31 be ready to protect your pennyroyal if you have one of those late frosts.

USDA Zone Info for National City

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in National City

You may be interested in your other planting guides for National City.