One of the first steps you take when you are getting a good idea your gardening schedule is find your 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 read to figure out when it's the best time to plant purple bell vines.

Planting Calendar for Purple Bell Vines

Frost tolerance for purple bell vines:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant purple bell vines just a tiny bit earlier in the year because they do ok in moderate cold.

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

Last Frost Date

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

Keep in mind that USDA zone info for San Francisco may not be accurate from year to year and the actual date of last frost can change quite a bit 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 purple bell vines 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.