One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Perris you should be able to figure out when it's a good idea to plant cosmos.

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 get them planted just a bit earlier than other plants that might not handle the cold.

The earliest that you can plant cosmos in Perris 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. Any later than that and your cosmos may not have a chance to really do well. If you are starting your cosmos indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Perris the average date of last frost happens on February 15. You should expect an average low temperature of 25°F in the coldest months of winter.

It's important to remember that USDA zone info for Perris may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Perris you get a frost after February 15 so be sure to be ready to protect your cosmos in the event of one of those late frosts.

USDA Zone Info for Perris

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 Perris

You may be interested in your other planting guides for Perris.