When to Plant Cosmos in Vermilion, OH

Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Vermilion can be used to determine when to plant cosmos.


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 one of those plants that can tolerate a tiny bit of cold weather which tells us that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

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 Vermilion 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. If you wait any later than that and your cosmos may not have a chance to fully mature. Starting your cosmos indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Vermilion the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -10°F.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Vermilion and it is different every year. Since half of the time in Vermilion you get a frost after April 15 be ready to protect your cosmos in the event of a late frost.

USDA Zone Info for Vermilion

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 Vermilion

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