One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when it's a good idea to plant calendula by reviewing the USDA zone info for Portola Valley.

Planting Calendar for Calendula

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

You can plant calendula just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant calendula 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 calendula and expect a good harvest is probably October. Any later than that and your calendula may not have a chance to fully mature. Starting your calendula indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Portola Valley the average date of last frost happens on January 31. You should expect an average low temperature of 30°F in the coldest months of winter.

Keep in mind that USDA zone info for Portola Valley is an average and the actual date of last frost will vary from year to year. Since half of the time in Portola Valley it frosts late in the year after January 31 be ready to cover your calendula 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.