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

You can figure out when you can plant cosmos in Red Bluff by reviewing 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.

Cosmos do ok in moderate cold which tells us that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant cosmos in Red Bluff 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. You can get started a few weeks earlier by starting your cosmos indoors.

Last Frost Date

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

Always keep in mind that USDA zone info for Red Bluff 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 Red Bluff you get a frost after February 15 so just be sure to be ready to cover your cosmos in the event of a late frost.

USDA Zone Info for Red Bluff

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 Red Bluff

You may be interested in your other planting guides for Red Bluff.