The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. 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 should be looked at to determine when it's possible to plant borage.

Planting Calendar for Borage

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

Borage can survive in moderate cold which means that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant borage 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 borage and expect a good harvest is probably October. Any later than that and your borage may not have a chance to grow to maturity. If you are starting your borage indoors then you might be able to get away with starting them a couple of weeks earlier.

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 USDA zone info for San Francisco is just an average and the actual date of last frost will vary from year to year. Since half of the time in San Francisco there is a last frost after January 31 be ready to cover your borage if you have 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.