One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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.

The USDA zone info for San Luis Obispo should be read 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.

Four O' Clock do not do well in cold weather which means that you really should wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant four o' clock in San Luis Obispo 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. 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 little bit earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in San Luis Obispo. You should expect an average low temperature of 25°F in the coldest months of winter.

Always keep in mind that USDA zone info for San Luis Obispo is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in San Luis Obispo you get surprised by a frost after February 15 be ready to cover your four o' clock in the event of a surprise late frost.

USDA Zone Info for San Luis Obispo

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 San Luis Obispo

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