One of the first steps you take when you are estimating your gardening schedule is find your 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 first opportunity to plant sorrel in Portola Valley should be determined by referring to the USDA zone info.

Planting Calendar for Sorrel

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

Since sorrel are one of those plants that can tolerate a little bit of cold weather you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant sorrel 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 sorrel and expect a good harvest is probably October. Any later than that and your sorrel may not have a chance to fully mature. If you are starting your sorrel indoors then you might be able to get away with starting them a few 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.

Since the USDA zone info for Portola Valley is not always accurate the actual date of last frost 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 sorrel if you have a surprise late frost.

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.