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.

A way of figuring out when it's the best time to plant leeks is to look at the USDA zone info for San Francisco.

Planting Calendar for Leeks

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

Leeks are very cold tolerant which tells us that you can start planting them much earlier than more sensitive plants.

The earliest that you can plant leeks in San Francisco 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 leeks and expect a good harvest is probably October. You probably don't want to wait any later than that or else your leeks may not have a chance to fully mature. Starting your leeks indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is January 31 in San Francisco. You can expect an average low temperature of 35°F in the coldest months of winter.

Since the USDA zone info for San Francisco is just an average the actual date of last frost will vary from year to year. Since half of the time in San Francisco you get surprised by a frost after January 31 be ready to protect your leeks in the event of 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.