Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Watertown you should be able to figure out when it's a good idea to plant hardy asters.

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 just a tiny bit 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 Watertown 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. You probably don't want to wait any later than that or else your hardy asters may not have a chance to fully mature. You can get started a little bit earlier by starting your hardy asters indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Watertown. In the coldest months of winter you can expect an average low temperature of -5°F.

Since the USDA zone info for Watertown may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Watertown last frost occurs after April 15 be ready to protect your hardy asters in the event of one of those late frosts.

USDA Zone Info for Watertown

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Watertown

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