Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for El Cajon should be used to estimate when to plant penstemon.

Planting Calendar for Penstemon

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

Penstemon can survive in a little bit of cold which tells us that you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in El Cajon 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. If you wait any later than that and your penstemon may not have a chance to fully mature. Starting your penstemon indoors is a great way to get them started a little bit earlier.

Last Frost Date

In El Cajon the average date of last frost happens on January 31. You can expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for El Cajon is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in El Cajon last frost occurs after January 31 be ready to cover your penstemon if you have a surprise late frost.

USDA Zone Info for El Cajon

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 El Cajon

You may be interested in your other planting guides for El Cajon.