The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of determining when it's a good idea to plant calibrachoa is to consult the USDA zone info for Los Altos.

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.

Calibrachoa do ok in moderate cold which tells us that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant calibrachoa in Los Altos 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. You probably don't want to wait any later than that or else your calibrachoa may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your calibrachoa indoors.

Last Frost Date

On average all chance of frost has passed is on February 15 in Los Altos. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Los Altos is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Los Altos last frost occurs after February 15 be ready to protect your calibrachoa in the event of one of those late frosts.

USDA Zone Info for Los Altos

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 Los Altos

You may be interested in your other planting guides for Los Altos.