One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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.

The USDA zone info for San Jose should be read to estimate when to 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 a lot earlier in the year than more sensitive plants.

The earliest that you can plant radishes in San Jose 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. You probably don't want to wait any later than that or else your radishes may not have a chance to fully mature. Starting your radishes indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on February 15 in San Jose. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for San Jose is not always accurate the actual date of last frost is different every year. Half of the time in San Jose last frost occurs after February 15 so make sure that you are prepared to cover your radishes if you have one of those late frosts.

USDA Zone Info for San Jose

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in San Jose

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