One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Sonoma it's a good idea to determine when it's a good idea to plant petunias.

Planting Calendar for Petunias

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

You can plant petunias a bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant petunias in Sonoma 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 petunias and expect a good harvest is probably September. You probably don't want to wait any later than that or else your petunias may not have a chance to grow to maturity. Starting your petunias 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 Sonoma. You can expect an average low temperature of 25°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Sonoma and it will vary from year to year. Since half of the time in Sonoma last frost occurs after February 15 be ready to protect your petunias in the event of a late frost.

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.