The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Sonoma you can figure out when it's possible to plant celeriac by referring to the USDA zone info.

Planting Calendar for Celeriac

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

Since celeriac do well in moderate cold you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant celeriac 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 celeriac and expect a good harvest is probably October. Any later than that and your celeriac may not have a chance to really do well. Starting your celeriac indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Sonoma the average date of last frost happens on February 15. In the coldest months of winter you should expect an average low temperature of 25°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Sonoma and it can change quite a bit from year to year. Half of the time in Sonoma you get surprised by a frost after February 15 so make sure that you are prepared to cover your celeriac if you have a surprise 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.