Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to estimate when it's possible to plant trailing portulaca by referring to the USDA zone info for Atherton.

Planting Calendar for Trailing Portulaca

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

It's probably not a good idea to plant trailing portulaca until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant trailing portulaca in Atherton 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. You probably don't want to wait any later than that or else your trailing portulaca may not have a chance to fully mature. Starting your trailing portulaca indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Atherton the average date of last frost happens on February 15. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Atherton is an average the actual date of last frost changes from year to year. Half of the time in Atherton you get a frost after February 15 so make sure that you are prepared to protect your trailing portulaca in the event of a surprise late frost.

USDA Zone Info for Atherton

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 Atherton

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