One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Gretna you should be able to estimate 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.

Hardy Asters do well in mild cold which tells us that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant hardy asters in Gretna 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. Starting your hardy asters indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Gretna. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Gretna is an average the actual date of last frost is different every year. Since half of the time in Gretna it frosts late in the year after April 15 be ready to cover your hardy asters if you have a late frost.

USDA Zone Info for Gretna

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Gretna

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