The USDA Zone info is a great tool for gardeners to help us figure out 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.

In Sioux Center you can determine when to plant cosmos 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.

Since cosmos are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant cosmos in Sioux Center 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 grow to maturity. If you are starting your cosmos indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Sioux Center the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Sioux Center may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Sioux Center there is a last frost after April 15 so be sure to be ready to cover your cosmos in the event of a surprise late frost.

USDA Zone Info for Sioux Center

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 Sioux Center

You may be interested in your other planting guides for Sioux Center.