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

By using the USDA zone info for Calistoga you should be able to estimate when it's possible to plant trailing portulaca.

Planting Calendar for Trailing Portulaca

Frost tolerance for trailing portulaca:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's a bad idea to plant trailing portulaca until after the last frost because they require warm weather.

The earliest that you can plant trailing portulaca in Calistoga is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant trailing portulaca and expect a good harvest is probably September. If you wait any later than that and your trailing portulaca may not have a chance to grow to maturity. If you are starting your trailing portulaca indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Calistoga the average date of last frost happens on February 15. In the coldest months of winter you can expect an average low temperature of 20°F.

Since the USDA zone info for Calistoga may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Calistoga there is a last frost after February 15 so just be sure to be ready to cover your trailing portulaca if you have a late frost.

USDA Zone Info for Calistoga

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Calistoga

You may be interested in your other planting guides for Calistoga.