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

A common way of making a decision about when it's a good idea to plant campanula is to consult the USDA zone info for Sonora.

Planting Calendar for Campanula

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

Campanula do well in a little bit of cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant campanula in Sonora 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. 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

In Sonora the average date of last frost happens on February 15. It might get as low as 20°F during the coldest months of winter.

Keep in mind that USDA zone info for Sonora is just an average and the actual date of last frost changes from year to year. Half of the time in Sonora you get a frost after February 15 so just be sure to be ready to protect your campanula if you have a late frost.

USDA Zone Info for Sonora

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Sonora

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