When to Plant Cosmos in Osawatomie, KS

One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant cosmos in Osawatomie should be estimated 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.

Since cosmos are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than other frost tender 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 Osawatomie 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. Any later than that and your cosmos may not have a chance to really do well. You can get started a couple of weeks earlier by starting your cosmos indoors.

Last Frost Date

The average date of last frost is April 15 in Osawatomie. In the coldest months of winter you can expect an average low temperature of -10°F.

Keep in mind that USDA zone info for Osawatomie may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Osawatomie there is a last frost after April 15 so just be sure to be ready to cover your cosmos in the event of one of those late frosts.

USDA Zone Info for Osawatomie

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-10°F
Highest Expected Low-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Osawatomie

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