One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Madison you should be able to determine when to plant dahlias.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

You should not plant dahlias until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant dahlias in Madison 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 dahlias and expect a good harvest is probably August. Any later than that and your dahlias may not have a chance to grow to maturity. If you are starting your dahlias indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Madison is an average the actual date of last frost will vary from year to year. Since half of the time in Madison you get surprised by a frost after April 15 be ready to protect your dahlias if you have one of those late frosts.

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.