The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 determine when it's the best time to plant black radish.

Planting Calendar for Black radish

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

You can plant black radish a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant black radish 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 black radish and expect a good harvest is probably October. Any later than that and your black radish may not have a chance to grow to maturity. If you are starting your black radish indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In San Francisco the average date of last frost happens on January 31. It might get as low as 35°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for San Francisco and it is different every year. Since half of the time in San Francisco it frosts late in the year after January 31 be ready to protect your black radish 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.