One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can figure out when it's possible to plant spinach in San Francisco by referring to the USDA zone info.

Planting Calendar for Spinach

Frost tolerance for spinach:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since spinach are moderately cold tolerant you can plant them just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant spinach 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 spinach and expect a good harvest is probably October. If you wait any later than that and your spinach may not have a chance to grow to maturity. If you are starting your spinach indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for San Francisco may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in San Francisco there is a last frost after January 31 be ready to protect your spinach 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.