One of the first steps you take when you are figuring out your gardening schedule is find your 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.

One way of estimating when it's possible to plant hardy asters is to look at the USDA zone info for San Diego.

Planting Calendar for Hardy Asters

Frost tolerance for hardy asters:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since hardy asters are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant hardy asters in San Diego is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant hardy asters and expect a good harvest is probably September. Any later than that and your hardy asters may not have a chance to grow to maturity. Starting your hardy asters indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in San Diego. In the coldest months of winter you should expect an average low temperature of 20°F.

Since the USDA zone info for San Diego is not always accurate the actual date of last frost is different every year. Since half of the time in San Diego there is a last frost after February 15 be ready to cover your hardy asters if you have a 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.