One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In San Diego you can determine when it's a good idea to plant tithonia by checking out the USDA zone info.

Planting Calendar for Tithonia

Frost tolerance for tithonia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since tithonia do not do well in cold weather you need to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant tithonia in San Diego 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 tithonia and expect a good harvest is probably September. Any later than that and your tithonia may not have a chance to really do well. If you are starting your tithonia indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in San Diego. In the coldest months of winter you should expect an average low temperature of 20°F.

It's important to remember that USDA zone info for San Diego may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in San Diego last frost occurs after February 15 be ready to cover your tithonia in the event of a surprise late frost.

USDA Zone Info for San Diego

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in San Diego

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