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.

One way of getting a good idea when you can plant four o' clock is to look at the USDA zone info for San Diego.

Planting Calendar for Four O' Clock

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

Since four o' clock require warm weather it is important to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant four o' clock in San Diego 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 four o' clock and expect a good harvest is probably September. Any later than that and your four o' clock may not have a chance to fully mature. You can get started a little bit earlier by starting your four o' clock indoors.

Last Frost Date

The average date of last frost is January 31 in San Diego. You should expect an average low temperature of 35°F in the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for San Diego and it changes from year to year. Half of the time in San Diego you get a frost after January 31 so make sure that you are prepared to cover your four o' clock in the event of one of those late frosts.

USDA Zone Info for San Diego

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in San Diego

You may be interested in your other planting guides for San Diego.