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 referring to the USDA zone info for Portola Valley you should be able to estimate when to plant coreopsis.

Planting Calendar for Coreopsis

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

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

The earliest that you can plant coreopsis 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 coreopsis and expect a good harvest is probably October. You probably don't want to wait any later than that or else your coreopsis may not have a chance to grow to maturity. You can get started a little bit earlier by starting your coreopsis indoors.

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 may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Portola Valley it frosts late in the year after January 31 so be sure to be ready to protect your coreopsis in the event of 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.