Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. 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 Grass Valley should be reffered to in order 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.

Hardy Asters are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant hardy asters in Grass Valley 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. Any later than that and your hardy asters may not have a chance to really do well. 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 Grass Valley. You should expect an average low temperature of 20°F in the coldest months of winter.

Remember that USDA zone info for Grass Valley is just an average and the actual date of last frost is different every year. Half of the time in Grass Valley it frosts late in the year after February 15 so just be sure to be ready to protect your hardy asters if you have a late frost.

USDA Zone Info for Grass Valley

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Grass Valley

You may be interested in your other planting guides for Grass Valley.