The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of figuring out when to plant hardy asters is to check out the USDA zone info for Waterloo.

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.

You can plant hardy asters slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant hardy asters in Waterloo 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 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. You can get started a few weeks earlier by starting your hardy asters indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Waterloo. You should expect an average low temperature of -20°F in the coldest months of winter.

It's important to remember that USDA zone info for Waterloo may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Waterloo you get surprised by a frost after April 15 so always be ready to protect your hardy asters in the event of one of those late frosts.

USDA Zone Info for Waterloo

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 Waterloo

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