Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Petaluma can be read to estimate when to plant nigella.

Planting Calendar for Nigella

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

Nigella do well in cold which tells us that you can get them planted much earlier than other frost tender plants.

The earliest that you can plant nigella 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 nigella and expect a good harvest is probably October. You probably don't want to wait any later than that or else your nigella may not have a chance to really do well. You can get started a little bit earlier by starting your nigella indoors.

Last Frost Date

In Petaluma 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.

It's important to remember that the actual date of last frost is just an average 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 prepared to protect your nigella 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.