One of the best tools that you have as gardeners to help us figure out 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 Glendora should be looked at to estimate when you can 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 one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant cosmos in Glendora 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 grow to maturity. You can get started a few weeks earlier by starting your cosmos indoors.

Last Frost Date

In Glendora the average date of last frost happens on January 31. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Glendora is just an average the actual date of last frost will vary from year to year. Since half of the time in Glendora there is a last frost after January 31 be ready to protect your cosmos in the event of a late frost.

USDA Zone Info for Glendora

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 Glendora

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