One of the best tools that you have as gardeners to help us estimate 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.

One way of getting a good idea when it's the best time to plant radishes is to refer to the USDA zone info for Portola Valley.

Planting Calendar for Radishes

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

Since radishes do well in cold you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant radishes in Portola Valley 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 grow to maturity. Starting your radishes indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Portola Valley. You can expect an average low temperature of 30°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Portola Valley and it can change quite a bit from year to year. Half of the time in Portola Valley it frosts late in the year after January 31 so make sure that you are ready to cover your radishes if you have one of those late frosts.

USDA Zone Info for Portola Valley

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Portola Valley

You may be interested in your other planting guides for Portola Valley.