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 first opportunity to plant penstemon in San Diego should be estimated by reviewing the USDA zone info.

Planting Calendar for Penstemon

Frost tolerance for penstemon:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Penstemon do well in moderate cold which means that you can plant them a little bit earlier than other frost tender plants.

The earliest that you can plant penstemon in San Diego 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 penstemon and expect a good harvest is probably October. You probably don't want to wait any later than that or else your penstemon may not have a chance to grow to maturity. If you are starting your penstemon indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in San Diego. It might get as low as 20°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for San Diego and it is different every year. Half of the time in San Diego it frosts late in the year after February 15 so be sure to be ready to protect your penstemon in the event of a surprise late frost.

USDA Zone Info for San Diego

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in San Diego

You may be interested in your other planting guides for San Diego.