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

A way of making a decision about when to plant cosmos is to use the USDA zone info for Shelbyville.

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 tells us that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant cosmos in Shelbyville 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

On average all chance of frost has passed is on April 15 in Shelbyville. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Shelbyville is an average the actual date of last frost changes from year to year. Half of the time in Shelbyville you get a frost after April 15 so make sure that you are prepared to cover your cosmos if you have a surprise late frost.

USDA Zone Info for Shelbyville

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 Shelbyville

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