One of the first steps you take when you are figuring out your gardening schedule is find your 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 USDA zone info for Edwardsville should be read to estimate when it's a good idea 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.

Since cosmos are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant cosmos in Edwardsville 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 few weeks earlier by starting your cosmos indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Edwardsville. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Edwardsville may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Edwardsville it frosts late in the year after April 15 so make sure that you are ready to cover your cosmos in the event of a surprise late frost.

USDA Zone Info for Edwardsville

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 Edwardsville

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