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.

A way of getting a good idea when you can plant hardy asters is to examine the USDA zone info for Atherton.

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 tend to make it in mild cold which means that you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant hardy asters in Atherton is February. However, you really should wait until March 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 September. If you wait any later than that and 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

The average date of last frost is February 15 in Atherton. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Atherton is not always accurate the actual date of last frost will vary from year to year. Half of the time in Atherton there is a last frost after February 15 so be sure to be ready to cover your hardy asters if you have one of those late frosts.

USDA Zone Info for Atherton

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Atherton

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