One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Riverside can be looked at to figure out when to plant portulaca.

Planting Calendar for Portulaca

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

You really shouldn't plant portulaca until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant portulaca in Riverside 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. Any later than that and your portulaca may not have a chance to really do well. You can get started a little bit earlier by starting your portulaca indoors.

Last Frost Date

The average date of last frost is February 15 in Riverside. In the coldest months of winter you can expect an average low temperature of 25°F.

Just be sure to remember that USDA zone info for Riverside is just an average and the actual date of last frost will vary from year to year. Half of the time in Riverside you get a frost after February 15 so make sure that you are prepared to protect your portulaca in the event of a late frost.

USDA Zone Info for Riverside

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 Riverside

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