When can I plant Cosmos in Zone 8b

Before planting it is a good idea to find our USDA Zone info to determine our garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for our area.

By using the USDA zone info for Zone 8b you will be able to estimate when it's the best time to plant cosmos.


Planting Calendar for Cosmos

Frost tolerance for cosmos: Tolerant of a very small amount of frost.
When you should plant them: Up to 3 weeks before last frost.

Cosmos are barely cold tolerant which means that you can plant them slightly earlier than more sensitive plants.

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 8b is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant cosmos and expect a good harvest is probably August. You probably don't want to wait any later than that or else your cosmos may not have a chance to grow to maturity. Starting your cosmos indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Zone 8b. It might get as low as 15°F during the coldest months of winter.

It's important to remember that USDA zone info for Zone 8b is not always accurate and our actual date of last frost is different every year. Since half of the time in Zone 8b there is a last frost after March 15 be ready to protect your cosmos if we have a late frost.

USDA Zone Info for Zone 8b

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)March 15
Average Date of First Frost (fall)November 15
Lowest Expected Low15°F
Highest Expected Low20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Zone 8b

You may be interested in our other planting guides for Zone 8b.