One of the first steps you take when you are determining 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.

You can determine when to plant primroses in Sonoma by using the USDA zone info.

Planting Calendar for Primroses

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

Since primroses are one of those plants that can tolerate quite a bit of cold weather you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant primroses 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 primroses and expect a good harvest is probably October. If you wait any later than that and your primroses may not have a chance to really do well. If you are starting your primroses indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Sonoma and it can change quite a bit from year to year. Since half of the time in Sonoma you get surprised by a frost after February 15 be ready to protect your primroses if you have one of those late frosts.

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.