When to Plant Cosmos in Madison, WI

The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when it's possible to plant cosmos by reviewing the USDA zone info for Madison.


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 do ok in very little cold which means that you can plant them just a tiny bit earlier in the year than more sensitive plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant cosmos
Possibly ok, but a risky time to plant cosmos
Probably not a good time to plant cosmos

The earliest that you can plant cosmos in Madison 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. Starting your cosmos indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Madison the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -20°F.

Just be sure to remember that USDA zone info for Madison is not always accurate and the actual date of last frost is different every year. Since half of the time in Madison it frosts late in the year after April 15 be ready to cover your cosmos if you have a late frost.

USDA Zone Info for Madison

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 Madison

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