Before planting it is a good idea to find your USDA Zone info to determine 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.

In Rancho Mirage you can estimate when it's the best time to plant cosmos by referring to the USDA zone info.

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.

You can plant cosmos slightly earlier in the year because they are barely cold tolerant.

The earliest that you can plant cosmos in Rancho Mirage 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 grow to maturity. Starting your cosmos indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Rancho Mirage. It might get as low as 25°F during the coldest months of winter.

Remember that USDA zone info for Rancho Mirage 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 Rancho Mirage you get surprised by a frost after February 15 be ready to protect your cosmos if you have a surprise late frost.

USDA Zone Info for Rancho Mirage

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 Rancho Mirage

You may be interested in your other planting guides for Rancho Mirage.