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.

By reviewing the USDA zone info for Riverside you should be able to determine when it's possible to plant four o' clock.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's not a good idea to plant four o' clock until after the last frost because they require warm weather.

The earliest that you can plant four o' clock 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 four o' clock and expect a good harvest is probably September. If you wait any later than that and your four o' clock may not have a chance to really do well. If you are starting your four o' clock indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Riverside. It might get as low as 25°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Riverside and it will vary from year to year. Half of the time in Riverside last frost occurs after February 15 so make sure that you are ready to cover your four o' clock in the event of one of those late frosts.

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.