One of the best tools that you have as gardeners to help us figure out 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 USDA zone info for Palo Alto should be used to determine when it's the best time to plant calibrachoa.

Planting Calendar for Calibrachoa

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

You can plant calibrachoa slightly earlier in the year because they do ok in moderate cold.

The earliest that you can plant calibrachoa in Palo Alto 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 calibrachoa and expect a good harvest is probably September. Any later than that and your calibrachoa may not have a chance to really do well. You can get started a few weeks earlier by starting your calibrachoa indoors.

Last Frost Date

On average the last frost is on February 15 in Palo Alto. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Palo Alto is not always accurate the actual date of last frost changes from year to year. Half of the time in Palo Alto there is a last frost after February 15 so make sure that you are prepared to cover your calibrachoa if you have a surprise late frost.

USDA Zone Info for Palo Alto

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Palo Alto

You may be interested in your other planting guides for Palo Alto.