Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to estimate when it's possible to plant cosmos by looking at the USDA zone info for De Pere.

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 do ok in moderate cold.

The earliest that you can plant cosmos in De Pere 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 grow to maturity. Starting your cosmos indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In De Pere 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 De Pere is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in De Pere you get surprised by a frost after April 15 so make sure that you are prepared to protect your cosmos if you have one of those late frosts.

USDA Zone Info for De Pere

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 De Pere

You may be interested in your other planting guides for De Pere.