One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Delaware can be reffered to in order to figure out when 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 do ok in moderate cold.

The earliest that you can plant hardy asters in Delaware 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 grow to maturity. You can get started a couple of weeks 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 Delaware. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Delaware may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Delaware it frosts late in the year after April 15 so always be ready to cover your hardy asters if you have one of those late frosts.

USDA Zone Info for Delaware

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 Delaware

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