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

One way of figuring out when it's a good idea to plant violas is to consult the USDA zone info for South San Francisco.

Planting Calendar for Violas

Frost tolerance for violas:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant violas a lot earlier in the year because they do well in cold.

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

Last Frost Date

The average date of last frost is January 31 in South San Francisco. It might get as low as 30°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for South San Francisco and it can change quite a bit from year to year. Half of the time in South San Francisco last frost occurs after January 31 so just be sure to be ready to cover your violas if you have a late frost.

USDA Zone Info for South San Francisco

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in South San Francisco

You may be interested in your other planting guides for South San Francisco.