Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. 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 making a decision about when it's a good idea to plant cosmos is to examine the USDA zone info for Santa Ana.

Planting Calendar for Cosmos

Frost tolerance for cosmos:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Cosmos are barely cold tolerant which means that you can plant them slightly earlier than more sensitive plants.

The earliest that you can plant cosmos in Santa Ana 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 cosmos and expect a good harvest is probably September. If you wait any later than that and your cosmos may not have a chance to fully mature. Starting your cosmos indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on January 31 in Santa Ana. In the coldest months of winter you should expect an average low temperature of 30°F.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Santa Ana and it can change quite a bit from year to year. Since half of the time in Santa Ana it frosts late in the year after January 31 be ready to cover your cosmos in the event of a surprise late frost.

USDA Zone Info for Santa Ana

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 Santa Ana

You may be interested in your other planting guides for Santa Ana.