One of the first steps you take when you are determining 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.

In Riverside you can determine when it's the best time to plant osteospermum by reviewing the USDA zone info.

Planting Calendar for Osteospermum

Frost tolerance for osteospermum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since osteospermum do well in moderate cold you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant osteospermum in Riverside 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 osteospermum and expect a good harvest is probably September. If you wait any later than that and your osteospermum may not have a chance to fully mature. Starting your osteospermum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Riverside. In the coldest months of winter you can expect an average low temperature of -10°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Riverside and it changes from year to year. Half of the time in Riverside you get a frost after April 15 so always be ready to cover your osteospermum if you have a late frost.

USDA Zone Info for Riverside

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Riverside

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