One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of getting a good idea when it's a good idea to plant rosemary is to use the USDA zone info for Sonoma.

Planting Calendar for Rosemary

Frost tolerance for rosemary:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since rosemary are one of those plants that can tolerate quite a bit of cold weather you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant rosemary in Sonoma 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 rosemary and expect a good harvest is probably October. You probably don't want to wait any later than that or else your rosemary may not have a chance to fully mature. Starting your rosemary 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 USDA zone info for Sonoma is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Sonoma you get surprised by a frost after February 15 be ready to cover your rosemary 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.