One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Portola Valley you should be able to figure out when it's possible to plant oxalis.

Planting Calendar for Oxalis

Frost tolerance for oxalis:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Oxalis are not cold tolerant which means that it's necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant oxalis in Portola Valley is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant oxalis and expect a good harvest is probably September. If you wait any later than that and your oxalis may not have a chance to fully mature. You can get started a few weeks earlier by starting your oxalis indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in Portola Valley. You should expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for Portola Valley may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Portola Valley last frost occurs after January 31 be ready to cover your oxalis if you have a 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.