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.

By looking at the USDA zone info for San Francisco you will be able to estimate when it's possible to plant perilla.

Planting Calendar for Perilla

Frost tolerance for perilla:	Not tolerant of frost.
When to plant:	After the last frost.

You really shouldn't plant perilla until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant perilla in San Francisco is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant perilla and expect a good harvest is probably September. Any later than that and your perilla may not have a chance to grow to maturity. You can get started a little bit earlier by starting your perilla indoors.

Last Frost Date

On average the last frost has passed is on January 31 in San Francisco. In the coldest months of winter you should expect an average low temperature of 35°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for San Francisco and it changes from year to year. Since half of the time in San Francisco last frost occurs after January 31 be ready to protect your perilla if you have one of those late frosts.

USDA Zone Info for San Francisco

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in San Francisco

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