One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of making a decision about when you can plant cerastium is to check out the USDA zone info for San Francisco.

Planting Calendar for Cerastium

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

Cerastium do ok in mild cold which means that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant cerastium in 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 cerastium and expect a good harvest is probably October. Any later than that and your cerastium may not have a chance to fully mature. If you are starting your cerastium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In San Francisco the average date of last frost happens on January 31. You should expect an average low temperature of 35°F in the coldest months of winter.

It's important to remember that USDA zone info for San Francisco may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in San Francisco there is a last frost after January 31 be ready to cover your cerastium if you have a late frost.

USDA Zone Info for San Francisco

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in San Francisco

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