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 using the USDA zone info for San Diego you should be able to figure out when you can plant radishes.

Planting Calendar for Radishes

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

Since radishes are very cold tolerant you can plant them quite a bit earlier in the year than other frost tender 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 fully mature. Starting your radishes indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In San Diego the average date of last frost happens on January 31. In the coldest months of winter you can expect an average low temperature of 35°F.

Since the USDA zone info for San Diego may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in San Diego it frosts late in the year after January 31 be ready to cover your radishes if you have a late frost.

USDA Zone Info for San Diego

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 Diego

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