The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant pennyroyal in Rialto should be determined 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 are very cold tolerant 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 Rialto 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. Starting your pennyroyal indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Rialto. In the coldest months of winter you should expect an average low temperature of 30°F.

Always keep in mind that USDA zone info for Rialto is an average and the actual date of last frost is different every year. Since half of the time in Rialto there is a last frost after January 31 be ready to protect your pennyroyal in the event of a late frost.

USDA Zone Info for Rialto

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°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 35°F.

Plants to Grow in Rialto

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