The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant iresene in San Francisco can be figured out by reviewing the USDA zone info.

Planting Calendar for Iresene

Frost tolerance for iresene:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's not a good idea to plant iresene until after the last frost because they require warm weather.

The earliest that you can plant iresene 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 iresene and expect a good harvest is probably September. You probably don't want to wait any later than that or else your iresene may not have a chance to fully mature. If you are starting your iresene indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Francisco. You should expect an average low temperature of 35°F in the coldest months of winter.

It's important to remember that USDA zone info for San Francisco is an average and the actual date of last frost is different every year. Since half of the time in San Francisco you get a frost after January 31 be ready to cover your iresene if you have a surprise late frost.

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.