One of the best tools that you have as gardeners to help us estimate 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.

The USDA zone info for San Francisco can be reffered to in order to figure out when it's possible to plant calliopsis.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost.

You should not plant calliopsis until after the last frost because they require warm weather.

The earliest that you can plant calliopsis 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 calliopsis and expect a good harvest is probably September. Any later than that and your calliopsis may not have a chance to fully mature. You can get started a few weeks earlier by starting your calliopsis indoors.

Last Frost Date

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

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for San Francisco and it changes from year to year. Since half of the time in San Francisco there is a last frost after January 31 be ready to protect your calliopsis in the event of a surprise 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.