The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant cosmos in Charles City can be estimated by using 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.

You can plant cosmos a bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant cosmos in Charles City 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. 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 Charles City. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Charles City is not always accurate the actual date of last frost is different every year. Since half of the time in Charles City you get a frost after April 15 be ready to protect your cosmos if you have one of those late frosts.

USDA Zone Info for Charles City

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Charles City

You may be interested in your other planting guides for Charles City.