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.

The USDA zone info for Chelsea should be looked at to estimate when it's possible 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.

Since hardy asters are barely cold tolerant you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant hardy asters in Chelsea 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. Any later than that and your hardy asters may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your hardy asters indoors.

Last Frost Date

In Chelsea the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Just be sure to remember that USDA zone info for Chelsea is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Chelsea there is a last frost after April 15 be ready to cover your hardy asters if you have one of those late frosts.

USDA Zone Info for Chelsea

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 Chelsea

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