Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of figuring out when it's possible to plant nigella is to examine the USDA zone info for Rio Vista.

Planting Calendar for Nigella

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

Nigella are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them a quite a bit earlier than more sensitive plants.

The earliest that you can plant nigella in Rio Vista 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 fully mature. You can get started a couple of weeks earlier by starting your nigella indoors.

Last Frost Date

The average date of last frost is February 15 in Rio Vista. You should expect an average low temperature of 25°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Rio Vista and it can change quite a bit from year to year. Half of the time in Rio Vista you get surprised by a frost after February 15 so be sure to be ready to cover your nigella if you have a surprise late frost.

USDA Zone Info for Rio Vista

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 Rio Vista

You may be interested in your other planting guides for Rio Vista.