The USDA Zone info is a great tool for gardeners to help us estimate your gardening 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 you can plant campanula is to use the USDA zone info for San Luis Obispo.

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 moderate cold which means that you can start planting them earlier than more sensitive plants.

The earliest that you can plant campanula in San Luis Obispo 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. If you wait any later than that and your campanula may not have a chance to grow to maturity. Starting your campanula indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in San Luis Obispo. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for San Luis Obispo and it changes from year to year. Half of the time in San Luis Obispo you get surprised by a frost after February 15 so always be ready to protect your campanula in the event of one of those late frosts.

USDA Zone Info for San Luis Obispo

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 San Luis Obispo

You may be interested in your other planting guides for San Luis Obispo.