One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant spearmint in Sonoma should be figured out by referring to the USDA zone info.

Planting Calendar for Spearmint

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

Spearmint are one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them a quite a bit earlier than other frost tender plants.

The earliest that you can plant spearmint 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 spearmint and expect a good harvest is probably October. Any later than that and your spearmint may not have a chance to really do well. If you are starting your spearmint indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Sonoma the average date of last frost happens on February 15. 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 an average because it is based on the USDA zone info for Sonoma and it will vary from year to year. Since half of the time in Sonoma there is a last frost after February 15 be ready to cover your spearmint in the event of a 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.