One of the first steps you take when you are determining 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.

A way of estimating when to plant hardy asters is to look at the USDA zone info for Madison.

Planting Calendar for Hardy Asters

Frost tolerance for hardy asters:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Hardy Asters do ok in moderate cold which tells us that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant hardy asters 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 hardy asters and expect a good harvest is probably August. If you wait any later than that and your hardy asters may not have a chance to really do well. Starting your hardy asters indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Madison. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Madison may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Madison it frosts late in the year after May 15 so just be sure to be ready to cover your hardy asters in the event of a surprise late frost.

USDA Zone Info for Madison

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Madison

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