The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to estimate when it's a good idea to plant hardy asters by referring to the USDA zone info for Santa Rosa.

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 barely cold tolerant which tells us that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant hardy asters in Santa Rosa 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 little bit earlier.

Last Frost Date

In Santa Rosa the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that USDA zone info for Santa Rosa is just an average and the actual date of last frost is different every year. Half of the time in Santa Rosa there is a last frost after February 15 so make sure that you are ready to protect your hardy asters in the event of a surprise late frost.

USDA Zone Info for Santa Rosa

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 Santa Rosa

You may be interested in your other planting guides for Santa Rosa.