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.

In Portola Valley you can figure out when it's possible to plant string beans by looking at the USDA zone info.

Planting Calendar for String beans

Frost tolerance for string beans:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's not a good idea to plant string beans until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant string beans in Portola Valley 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. If you wait any later than that and your string beans may not have a chance to really do well. Starting your string beans indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Portola Valley the average date of last frost happens on January 31. In the coldest months of winter you can expect an average low temperature of 30°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Portola Valley and it is different every year. Since half of the time in Portola Valley it frosts late in the year after January 31 be ready to protect your string beans in the event of a surprise late frost.

USDA Zone Info for Portola Valley

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 Portola Valley

You may be interested in your other planting guides for Portola Valley.