The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for San Luis should be reviewed to figure out 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.

Since four o' clock do not do well in cold weather you must wait until after the last frost before you can plant them.

The earliest that you can plant four o' clock in San Luis 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. You probably don't want to wait any later than that or else your four o' clock may not have a chance to grow to maturity. Starting your four o' clock indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Luis. It might get as low as 30°F during the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for San Luis and it can change quite a bit from year to year. Since half of the time in San Luis you get surprised by a frost after January 31 be ready to protect your four o' clock if you have a late frost.

USDA Zone Info for San Luis

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in San Luis

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