One of the first steps you take when you are determining 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 USDA zone info for San Francisco can be used to figure out when you can plant portulaca.

Planting Calendar for Portulaca

Frost tolerance for portulaca:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since portulaca require warm weather you really should wait until after the last frost before you can plant them.

The earliest that you can plant portulaca in San Francisco 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 portulaca and expect a good harvest is probably September. Any later than that and your portulaca may not have a chance to really do well. You can get started a few weeks earlier by starting your portulaca indoors.

Last Frost Date

The average date of last frost is January 31 in San Francisco. It might get as low as 35°F during the coldest months of winter.

It's important to remember that USDA zone info for San Francisco is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in San Francisco last frost occurs after January 31 so make sure that you are ready to cover your portulaca if you have one of those late frosts.

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.