Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant radishes in San Diego can be estimated by using the USDA zone info.

Planting Calendar for Radishes

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

Radishes do ok in a bit of cold which tells us that you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant radishes in San Diego 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 radishes and expect a good harvest is probably October. Any later than that and your radishes may not have a chance to really do well. Starting your radishes indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in San Diego. In the coldest months of winter you should expect an average low temperature of 20°F.

Just be sure to remember that USDA zone info for San Diego is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in San Diego it frosts late in the year after February 15 so always be ready to cover your radishes in the event of one of those late frosts.

USDA Zone Info for San Diego

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in San Diego

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