One of the best tools that you have as gardeners to help us estimate 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.

One way of getting a good idea when it's possible to plant cosmos is to check out the USDA zone info for Brentwood.

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.

Since cosmos do ok in moderate cold you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant cosmos in Brentwood 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. You can get started a little bit earlier by starting your cosmos indoors.

Last Frost Date

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

Just be sure to remember that USDA zone info for Brentwood is just an average and the actual date of last frost will vary from year to year. Half of the time in Brentwood it frosts late in the year after February 15 so just be sure to be ready to protect your cosmos if you have a surprise late frost.

USDA Zone Info for Brentwood

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 Brentwood

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