Before planting it is a good idea to find your USDA Zone info to estimate 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.

In Chicago you can figure out when it's possible to plant dahlia by using the USDA zone info.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost.

It's not a good idea to plant dahlia until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant dahlia in Chicago is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant dahlia and expect a good harvest is probably August. Any later than that and your dahlia may not have a chance to grow to maturity. You can get started a little bit earlier by starting your dahlia indoors.

Last Frost Date

The average date of last frost is April 15 in Chicago. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Chicago is just an average the actual date of last frost changes from year to year. Half of the time in Chicago it frosts late in the year after April 15 so always be ready to protect your dahlia if you have one of those late frosts.

USDA Zone Info for Chicago

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 Chicago

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