One of the first steps you take when you are determining your gardening schedule is find your 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 earliest that you can plant hardy asters in Tucson can be determined by looking at the USDA zone info.

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 plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant hardy asters in Tucson 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 grow to maturity. You can get started a few weeks earlier by starting your hardy asters indoors.

Last Frost Date

On average the last frost has passed is on February 15 in Tucson. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Tucson may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Tucson last frost occurs after February 15 be ready to cover your hardy asters if you have one of those late frosts.

USDA Zone Info for Tucson

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 Tucson

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