One of the first steps you take when you are determining 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.

The USDA zone info for Portola Valley should be looked at to figure out when you can plant regal geranium.

Planting Calendar for Regal Geranium

Frost tolerance for regal geranium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since regal geranium are barely cold tolerant you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant regal geranium 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 regal geranium and expect a good harvest is probably September. You probably don't want to wait any later than that or else your regal geranium may not have a chance to grow to maturity. Starting your regal geranium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Portola Valley may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Portola Valley you get a frost after January 31 so make sure that you are ready to cover your regal geranium 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.