The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant campanula in Portola Valley can be determined by using the USDA zone info.

Planting Calendar for Campanula

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

Campanula are one of those plants that can tolerate a little bit of cold weather which means that you can start planting them earlier than more sensitive plants.

The earliest that you can plant campanula in Portola Valley 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 campanula and expect a good harvest is probably October. You probably don't want to wait any later than that or else your campanula may not have a chance to grow to maturity. Starting your campanula indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Portola Valley and it will vary from year to year. Half of the time in Portola Valley last frost occurs after January 31 so just be sure to be ready to cover your campanula if you have one of those late frosts.

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.