Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant campanula in Sonoma should be determined by looking at 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 moderately cold tolerant which tells us that you can get them planted earlier than other plants that might not handle the cold.

The earliest that you can plant campanula in Sonoma 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 really do well. If you are starting your campanula indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Sonoma. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Sonoma may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Sonoma there is a last frost after February 15 be ready to cover your campanula in the event of one of those late frosts.

USDA Zone Info for Sonoma

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Sonoma

You may be interested in your other planting guides for Sonoma.