The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In San Luis Obispo you can figure out when it's a good idea to plant spearmint 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.

Since spearmint are very cold tolerant you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant spearmint in San Luis Obispo 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 fully mature. You can get started a little bit earlier by starting your spearmint indoors.

Last Frost Date

On average the last frost is on February 15 in San Luis Obispo. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for San Luis Obispo is an average the actual date of last frost is different every year. Half of the time in San Luis Obispo there is a last frost after February 15 so make sure that you are prepared to protect your spearmint in the event of a surprise late frost.

USDA Zone Info for San Luis Obispo

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 San Luis Obispo

You may be interested in your other planting guides for San Luis Obispo.