One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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 osteospermum in Portola Valley can be determined by referring to the USDA zone info.

Planting Calendar for Osteospermum

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

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

The earliest that you can plant osteospermum 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 osteospermum and expect a good harvest is probably October. If you wait any later than that and your osteospermum may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your osteospermum 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.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Portola Valley and it will vary from year to year. Half of the time in Portola Valley you get surprised by a frost after January 31 so always be ready to protect your osteospermum 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.