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.

A common way of determining when you can plant string beans is to consult the USDA zone info for South San Francisco.

Planting Calendar for String beans

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

String beans do not do well in cold weather which means that it's necessary to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant string beans in South 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 string beans and expect a good harvest is probably September. You probably don't want to wait any later than that or else your string beans may not have a chance to fully mature. You can get started a few weeks earlier by starting your string beans indoors.

Last Frost Date

The average date of last frost is January 31 in South San Francisco. You can expect an average low temperature of 30°F in the coldest months of winter.

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 is different every year. Since half of the time in South San Francisco last frost occurs after January 31 be ready to cover your string beans in the event of 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.