The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for San Francisco should be reviewed to determine when you can plant begonias.

Planting Calendar for Begonias

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

Since begonias require warm weather it is important to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant begonias 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 begonias and expect a good harvest is probably September. Any later than that and your begonias may not have a chance to really do well. If you are starting your begonias indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on January 31 in San Francisco. In the coldest months of winter you can expect an average low temperature of 35°F.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for San Francisco and it can change quite a bit from year to year. Half of the time in San Francisco there is a last frost after January 31 so make sure that you are prepared to cover your begonias 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.