One of the first steps you take when you are estimating 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.

The earliest that you can plant asters in South San Francisco can be figured out by reviewing the USDA zone info.

Planting Calendar for Asters

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

Asters can survive in some cold which tells us that you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant asters in South San Francisco 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 asters and expect a good harvest is probably October. Any later than that and your asters may not have a chance to grow to maturity. Starting your asters indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on January 31 in South San Francisco. It might get as low as 30°F during the coldest months of winter.

Just be sure to remember that USDA zone info for South San Francisco is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in South San Francisco there is a last frost after January 31 be ready to protect your asters in the event of a late frost.

USDA Zone Info for South San Francisco

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 South San Francisco

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