Before planting it is a good idea to find your USDA Zone info to estimate 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.

One way of determining when it's possible to plant campanula is to look at the USDA zone info for Napa.

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 tells us that you can plant them earlier than other frost tender plants.

The earliest that you can plant campanula in Napa 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. Any later than that and your campanula may not have a chance to really do well. You can get started a little bit earlier by starting your campanula indoors.

Last Frost Date

The average date of last frost is February 15 in Napa. In the coldest months of winter you should expect an average low temperature of 25°F.

Just be sure to remember that USDA zone info for Napa is not always accurate and the actual date of last frost is different every year. Half of the time in Napa you get a frost after February 15 so make sure that you are ready to protect your campanula if you have a late frost.

USDA Zone Info for Napa

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 Napa

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