When to Plant Cosmos in Zone 11a

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.

The USDA zone info for Zone 11a should be looked at to estimate when you can plant cosmos.

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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 one of those plants that can tolerate a tiny bit of cold weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant cosmos
Possibly ok, but a risky time to plant cosmos
Probably not a good time to plant cosmos

The earliest that you can plant cosmos in Zone 11a is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant cosmos and expect a good harvest is probably November. 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 Zone 11a it never frosts. It might get as low as 40°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Zone 11a and it changes from year to year. Since it never frosts in Zone 11a you do not have to be ready to protect your cosmos if you have one of those late frosts.

USDA Zone Info for Zone 11a

Here is the info for USDA Zone 11a.

Average Date of Last Frost (spring)Never
Average Date of First Frost (fall)Never
Lowest Expected Low40°F
Highest Expected Low45°F

This means that on a really cold year, the coldest it will get is 40°F. On most years you should be prepared to experience lows near 45°F.

Plants to Grow in Zone 11a

You may be interested in your other planting guides for Zone 11a.