The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Portola Valley you can determine when you can plant balloon flower by looking at the USDA zone info.

Planting Calendar for Balloon Flower

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

Balloon Flower are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant balloon flower 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 balloon flower and expect a good harvest is probably September. Any later than that and your balloon flower may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your balloon flower indoors.

Last Frost Date

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

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Portola Valley and it is different every year. Half of the time in Portola Valley it frosts late in the year after January 31 so make sure that you are prepared to cover your balloon flower 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.