When to Plant Cosmos in Bloomington, IL

Before planting it is a good idea to find your USDA Zone info to figure out 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 first chance to plant cosmos in Bloomington should be estimated by checking out 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 are barely cold tolerant which means that you can get them planted just a bit 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 Bloomington 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 fully mature. You can get started a little bit earlier by starting your cosmos indoors.

Last Frost Date

In Bloomington the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that USDA zone info for Bloomington is an average and the actual date of last frost changes from year to year. Half of the time in Bloomington last frost occurs after April 15 so just be sure to be ready to cover your cosmos in the event of a late frost.

USDA Zone Info for Bloomington

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-15°F
Highest Expected Low-10°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 -10°F.

Plants to Grow in Bloomington

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