The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Mill Valley you can figure out when you can plant sorrel 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.

You can plant sorrel just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant sorrel in Mill 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. If you wait any later than that and your sorrel may not have a chance to grow to maturity. If you are starting your sorrel indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Mill Valley. In the coldest months of winter you should expect an average low temperature of 30°F.

Since the USDA zone info for Mill Valley is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Mill Valley it frosts late in the year after January 31 be ready to protect your sorrel in the event of a surprise late frost.

USDA Zone Info for Mill 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 Mill Valley

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