The USDA Zone info is a great tool for gardeners to help us determine 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.

By looking at the USDA zone info for Petaluma you should be able to figure out when it's the best time to plant calibrachoa.

Planting Calendar for Calibrachoa

Frost tolerance for calibrachoa:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Calibrachoa can survive in very little cold which means that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant calibrachoa in Petaluma is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant calibrachoa and expect a good harvest is probably September. Any later than that and your calibrachoa may not have a chance to really do well. Starting your calibrachoa indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Petaluma. It might get as low as 25°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Petaluma and it changes from year to year. Half of the time in Petaluma there is a last frost after February 15 so make sure that you are ready to cover your calibrachoa if you have one of those late frosts.

USDA Zone Info for Petaluma

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 Petaluma

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