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.

The USDA zone info for Petaluma should be looked at to figure out when it's the best time to plant celeriac.

Planting Calendar for Celeriac

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

You can plant celeriac a little earlier in the year because they do well in moderate cold.

The earliest that you can plant celeriac in Petaluma 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. If you wait any later than that and your celeriac may not have a chance to really do well. If you are starting your celeriac indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in Petaluma. In the coldest months of winter you can expect an average low temperature of 25°F.

Just be sure to remember that USDA zone info for Petaluma may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Petaluma you get surprised by a frost after February 15 be ready to cover your celeriac in the event of a surprise late frost.

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.