One of the first steps you take when you are estimating your gardening schedule is find your 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.

By looking at the USDA zone info for Atherton you will be able to estimate when you can plant portulaca.

Planting Calendar for Portulaca

Frost tolerance for portulaca:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Portulaca are not cold tolerant which means that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant 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 portulaca and expect a good harvest is probably September. If you wait any later than that and your portulaca may not have a chance to really do well. You can get started a few weeks earlier by starting your portulaca indoors.

Last Frost Date

On average the last frost has passed is on February 15 in Atherton. You can expect an average low temperature of 25°F in the coldest months of winter.

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 Atherton and it can change quite a bit from year to year. Since half of the time in Atherton it frosts late in the year after February 15 be ready to cover your portulaca in the event of a 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.